transport: set default header list size to 8KB and guard behind an env variable. by Pranjali-2501 · Pull Request #9019 · grpc/grpc-go

Pranjali-2501 · 2026-03-25T16:58:35Z

Part of: #2308

Follow up of PR: #8845

This PR implements a change to restrict the default maximum header list size to 8KB. The change is guarded by a new environment variable GRPC_GO_EXPERIMENTAL_DEFAULT_HEADER_LIST_SIZE, which is disabled by default.

When the environment variable is disabled (default), the legacy default of 16MB is used. When enabled, RPCs with a total size of headers exceeding 8KB will fail unless explicitly configured otherwise by the user.

Changes

internal/envconfig

Added DefaultHeaderListSize: A boolean flag controlled by the GRPC_GO_EXPERIMENTAL_DEFAULT_HEADER_LIST_SIZE environment variable.

internal/transport/http2_client.go and internal/transport/http2_server.go

Use upcomingDefaultHeaderListSize (8KB) as the default value if DefaultHeaderListSize is enabled.
If env variable is disabled and header size is greater than upcomingDefaultHeaderListSize, log a warning.

RELEASE NOTES:

transport: change default header list size from 16MB to 8KB and guard it behind GRPC_GO_EXPERIMENTAL_DEFAULT_HEADER_LIST_SIZE env var which is disabled by default. The env var will be enabled by default in v1.82.0 release.

codecov · 2026-03-25T17:02:26Z

Codecov Report

❌ Patch coverage is 55.55556% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.84%. Comparing base (ccc8d7b) to head (95a6789).
⚠️ Report is 36 commits behind head on master.

Files with missing lines	Patch %	Lines
internal/transport/http2_server.go	50.00%	2 Missing ⚠️
internal/envconfig/envconfig.go	0.00%	1 Missing ⚠️
internal/transport/http2_client.go	75.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #9019      +/-   ##
==========================================
- Coverage   82.99%   81.84%   -1.16%     
==========================================
  Files         411      413       +2     
  Lines       32917    33427     +510     
==========================================
+ Hits        27319    27357      +38     
- Misses       4196     4266      +70     
- Partials     1402     1804     +402

Files with missing lines	Coverage Δ
internal/envconfig/envconfig.go	`73.33% <0.00%> (-26.67%)`	⬇️
internal/transport/http2_client.go	`70.56% <75.00%> (-22.29%)`	⬇️
internal/transport/http2_server.go	`68.82% <50.00%> (-22.14%)`	⬇️

... and 53 files with indirect coverage changes

🚀 New features to boost your workflow:

❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

easwars

We need tests to verify the behavior with the newly added env var. Or do we have some already?

easwars · 2026-04-15T19:05:51Z

Please consider putting the information that the env var will be enabled by default starting 1.82 so users will get a heads up.

…v variable. (grpc#9019) Part of: grpc#2308 Follow up of PR: grpc#8845 This PR implements a change to restrict the default maximum header list size to 8KB. The change is guarded by a new environment variable GRPC_GO_EXPERIMENTAL_DEFAULT_HEADER_LIST_SIZE, which is disabled by default. When the environment variable is disabled (default), the legacy default of 16MB is used. When enabled, RPCs with a total size of headers exceeding 8KB will fail unless explicitly configured otherwise by the user. ## Changes `internal/envconfig` * Added DefaultHeaderListSize: A boolean flag controlled by the GRPC_GO_EXPERIMENTAL_DEFAULT_HEADER_LIST_SIZE environment variable. `internal/transport/http2_client.go` and `internal/transport/http2_server.go` * Use upcomingDefaultHeaderListSize (8KB) as the default value if `DefaultHeaderListSize` is enabled. * If env variable is disabled and header size is greater than upcomingDefaultHeaderListSize, log a warning. RELEASE NOTES: * transport: change default header list size from 16MB to 8KB and guard it behind `GRPC_GO_EXPERIMENTAL_DEFAULT_HEADER_LIST_SIZE` env var which is disabled by default. The env var will be enabled by default in v1.82.0 release.

…(#17) This PR contains the following updates: | Package | Change | [Age](https://docs.renovatebot.com/merge-confidence/) | [Confidence](https://docs.renovatebot.com/merge-confidence/) | |---|---|---|---| | [google.golang.org/grpc](https://github.com/grpc/grpc-go) | `v1.81.1` → `v1.82.0` | ![age](https://developer.mend.io/api/mc/badges/age/go/google.golang.org%2fgrpc/v1.82.0?slim=true) | ![confidence](https://developer.mend.io/api/mc/badges/confidence/go/google.golang.org%2fgrpc/v1.81.1/v1.82.0?slim=true) | --- ### Release Notes <details> <summary>grpc/grpc-go (google.golang.org/grpc)</summary> ### [`v1.82.0`](https://github.com/grpc/grpc-go/releases/tag/v1.82.0): Release 1.82.0 [Compare Source](grpc/grpc-go@v1.81.1...v1.82.0) ### Behavior Changes - server: Remove support for `GRPC_GO_EXPERIMENTAL_DISABLE_STRICT_PATH_CHECKING` environment varibale. Strict incoming RPC path validation (which has been the default since `v1.79.3`) can no longer be disabled. ([#9112](grpc/grpc-go#9112)) - transport: Add environment variable to change the default max header list size from `16MB` to `8KB`. This may be enabled by setting `GRPC_GO_EXPERIMENTAL_ENABLE_8KB_DEFAULT_HEADER_LIST_SIZE=true`. This will be enabled by default in a subsequent release. ([#9019](grpc/grpc-go#9019)) - balancer: Load Balancing policy registry is now case-sensitive. Set `GRPC_GO_EXPERIMENTAL_CASE_SENSITIVE_BALANCER_REGISTRIES=false` (and file an issue) to revert to case-insensitive behavior. ([#9017](grpc/grpc-go#9017)) ### New Features - experimental/stats: Expose a new API, `NewContextWithLabelCallback`, to register a callback that is invoked when telemetry labels are added. ([#8877](grpc/grpc-go#8877)) - Special Thanks: [@seth-epps](https://github.com/seth-epps) - client: Return a portion of the response body in the error message, when the client receives an unexpected non-gRPC HTTP response, to make debugging easier. ([#8929](grpc/grpc-go#8929)) - Special Thanks: [@chengxilo](https://github.com/chengxilo) - server: Add environment variable `GRPC_GO_SERVER_GOROUTINE_LABELS` that controls setting `runtime/pprof.Labels` on goroutines spawned by the server. Set `GRPC_GO_SERVER_GOROUTINE_LABELS=grpc.method=true` to add the `grpc.method` label on goroutines spawned to handle incoming requests. ([#9082](grpc/grpc-go#9082)) - Special Thanks: [@dfinkel](https://github.com/dfinkel) ### Bug Fixes - xds/server: Fix a memory leak of HTTP filter instances occurring when route configurations are updated in-place during a Route Discovery Service (RDS) update. ([#9138](grpc/grpc-go#9138)) - grpc: In the deprecated `gzip` Compressor (used via the deprecated `WithCompressor` dial option), enforce the `MaxRecvMsgSize` limit on the decompressed message buffer, preventing excessive memory allocation from highly compressed payloads. ([#9114](grpc/grpc-go#9114)) - Special Thanks: [@evilgensec](https://github.com/evilgensec) - stats/opentelemetry: Record retry attempts, `grpc.previous-rpc-attempts`, at the call level and not the attempt level. ([#8923](grpc/grpc-go#8923)) - encoding: Ensure `Close()` is always called on readers returned from `Compressor.Decompress` if possible. ([#9135](grpc/grpc-go#9135)) - channelz: Fix the `LastMessageSentTimestamp` and `LastMessageReceivedTimestamp` fields in `SocketMetrics` to ensure they contain correct timestamp values. ([#9109](grpc/grpc-go#9109)) </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this PR, check this box --- This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).  Reviewed-on: https://git.erwanleboucher.dev/eleboucher/talos-mcp/pulls/17

…(#77) This PR contains the following updates: | Package | Change | [Age](https://docs.renovatebot.com/merge-confidence/) | [Confidence](https://docs.renovatebot.com/merge-confidence/) | |---|---|---|---| | [google.golang.org/grpc](https://github.com/grpc/grpc-go) | `v1.81.1` → `v1.82.0` | ![age](https://developer.mend.io/api/mc/badges/age/go/google.golang.org%2fgrpc/v1.82.0?slim=true) | ![confidence](https://developer.mend.io/api/mc/badges/confidence/go/google.golang.org%2fgrpc/v1.81.1/v1.82.0?slim=true) | --- ### Release Notes <details> <summary>grpc/grpc-go (google.golang.org/grpc)</summary> ### [`v1.82.0`](https://github.com/grpc/grpc-go/releases/tag/v1.82.0): Release 1.82.0 [Compare Source](grpc/grpc-go@v1.81.1...v1.82.0) ### Behavior Changes - server: Remove support for `GRPC_GO_EXPERIMENTAL_DISABLE_STRICT_PATH_CHECKING` environment varibale. Strict incoming RPC path validation (which has been the default since `v1.79.3`) can no longer be disabled. ([#9112](grpc/grpc-go#9112)) - transport: Add environment variable to change the default max header list size from `16MB` to `8KB`. This may be enabled by setting `GRPC_GO_EXPERIMENTAL_ENABLE_8KB_DEFAULT_HEADER_LIST_SIZE=true`. This will be enabled by default in a subsequent release. ([#9019](grpc/grpc-go#9019)) - balancer: Load Balancing policy registry is now case-sensitive. Set `GRPC_GO_EXPERIMENTAL_CASE_SENSITIVE_BALANCER_REGISTRIES=false` (and file an issue) to revert to case-insensitive behavior. ([#9017](grpc/grpc-go#9017)) ### New Features - experimental/stats: Expose a new API, `NewContextWithLabelCallback`, to register a callback that is invoked when telemetry labels are added. ([#8877](grpc/grpc-go#8877)) - Special Thanks: [@seth-epps](https://github.com/seth-epps) - client: Return a portion of the response body in the error message, when the client receives an unexpected non-gRPC HTTP response, to make debugging easier. ([#8929](grpc/grpc-go#8929)) - Special Thanks: [@chengxilo](https://github.com/chengxilo) - server: Add environment variable `GRPC_GO_SERVER_GOROUTINE_LABELS` that controls setting `runtime/pprof.Labels` on goroutines spawned by the server. Set `GRPC_GO_SERVER_GOROUTINE_LABELS=grpc.method=true` to add the `grpc.method` label on goroutines spawned to handle incoming requests. ([#9082](grpc/grpc-go#9082)) - Special Thanks: [@dfinkel](https://github.com/dfinkel) ### Bug Fixes - xds/server: Fix a memory leak of HTTP filter instances occurring when route configurations are updated in-place during a Route Discovery Service (RDS) update. ([#9138](grpc/grpc-go#9138)) - grpc: In the deprecated `gzip` Compressor (used via the deprecated `WithCompressor` dial option), enforce the `MaxRecvMsgSize` limit on the decompressed message buffer, preventing excessive memory allocation from highly compressed payloads. ([#9114](grpc/grpc-go#9114)) - Special Thanks: [@evilgensec](https://github.com/evilgensec) - stats/opentelemetry: Record retry attempts, `grpc.previous-rpc-attempts`, at the call level and not the attempt level. ([#8923](grpc/grpc-go#8923)) - encoding: Ensure `Close()` is always called on readers returned from `Compressor.Decompress` if possible. ([#9135](grpc/grpc-go#9135)) - channelz: Fix the `LastMessageSentTimestamp` and `LastMessageReceivedTimestamp` fields in `SocketMetrics` to ensure they contain correct timestamp values. ([#9109](grpc/grpc-go#9109)) </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this PR, check this box --- This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).  Reviewed-on: https://git.erwanleboucher.dev/eleboucher/runner-k8s-plugin/pulls/77

This PR contains the following updates: | Package | Change | [Age](https://docs.renovatebot.com/merge-confidence/) | [Confidence](https://docs.renovatebot.com/merge-confidence/) | |---|---|---|---| | [google.golang.org/grpc](https://github.com/grpc/grpc-go) | `v1.81.1` → `v1.82.0` | ![age](https://developer.mend.io/api/mc/badges/age/go/google.golang.org%2fgrpc/v1.82.0?slim=true) | ![confidence](https://developer.mend.io/api/mc/badges/confidence/go/google.golang.org%2fgrpc/v1.81.1/v1.82.0?slim=true) | --- ### Release Notes <details> <summary>grpc/grpc-go (google.golang.org/grpc)</summary> ### [`v1.82.0`](https://github.com/grpc/grpc-go/releases/tag/v1.82.0): Release 1.82.0 [Compare Source](grpc/grpc-go@v1.81.1...v1.82.0) ### Behavior Changes - server: Remove support for `GRPC_GO_EXPERIMENTAL_DISABLE_STRICT_PATH_CHECKING` environment varibale. Strict incoming RPC path validation (which has been the default since `v1.79.3`) can no longer be disabled. ([#9112](grpc/grpc-go#9112)) - transport: Add environment variable to change the default max header list size from `16MB` to `8KB`. This may be enabled by setting `GRPC_GO_EXPERIMENTAL_ENABLE_8KB_DEFAULT_HEADER_LIST_SIZE=true`. This will be enabled by default in a subsequent release. ([#9019](grpc/grpc-go#9019)) - balancer: Load Balancing policy registry is now case-sensitive. Set `GRPC_GO_EXPERIMENTAL_CASE_SENSITIVE_BALANCER_REGISTRIES=false` (and file an issue) to revert to case-insensitive behavior. ([#9017](grpc/grpc-go#9017)) ### New Features - experimental/stats: Expose a new API, `NewContextWithLabelCallback`, to register a callback that is invoked when telemetry labels are added. ([#8877](grpc/grpc-go#8877)) - Special Thanks: [@seth-epps](https://github.com/seth-epps) - client: Return a portion of the response body in the error message, when the client receives an unexpected non-gRPC HTTP response, to make debugging easier. ([#8929](grpc/grpc-go#8929)) - Special Thanks: [@chengxilo](https://github.com/chengxilo) - server: Add environment variable `GRPC_GO_SERVER_GOROUTINE_LABELS` that controls setting `runtime/pprof.Labels` on goroutines spawned by the server. Set `GRPC_GO_SERVER_GOROUTINE_LABELS=grpc.method=true` to add the `grpc.method` label on goroutines spawned to handle incoming requests. ([#9082](grpc/grpc-go#9082)) - Special Thanks: [@dfinkel](https://github.com/dfinkel) ### Bug Fixes - xds/server: Fix a memory leak of HTTP filter instances occurring when route configurations are updated in-place during a Route Discovery Service (RDS) update. ([#9138](grpc/grpc-go#9138)) - grpc: In the deprecated `gzip` Compressor (used via the deprecated `WithCompressor` dial option), enforce the `MaxRecvMsgSize` limit on the decompressed message buffer, preventing excessive memory allocation from highly compressed payloads. ([#9114](grpc/grpc-go#9114)) - Special Thanks: [@evilgensec](https://github.com/evilgensec) - stats/opentelemetry: Record retry attempts, `grpc.previous-rpc-attempts`, at the call level and not the attempt level. ([#8923](grpc/grpc-go#8923)) - encoding: Ensure `Close()` is always called on readers returned from `Compressor.Decompress` if possible. ([#9135](grpc/grpc-go#9135)) - channelz: Fix the `LastMessageSentTimestamp` and `LastMessageReceivedTimestamp` fields in `SocketMetrics` to ensure they contain correct timestamp values. ([#9109](grpc/grpc-go#9109)) </details> --- ### Configuration 📅 **Schedule**: (in timezone America/Los_Angeles) - Branch creation - At any time (no schedule defined) - Automerge - At any time (no schedule defined) 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this PR, check this box --- This PR has been generated by [Mend Renovate](https://github.com/renovatebot/renovate).  Co-authored-by: Renovate Bot <renovate-bot@geekfarm.org> Reviewed-on: https://git.geekfarm.org/wu/keyop-messenger/pulls/7

…/forgejo) (#13580) This PR contains the following updates: | Package | Change | [Age](https://docs.renovatebot.com/merge-confidence/) | [Confidence](https://docs.renovatebot.com/merge-confidence/) | |---|---|---|---| | [google.golang.org/grpc](https://github.com/grpc/grpc-go) | `v1.79.3` → `v1.82.1` | ![age](https://developer.mend.io/api/mc/badges/age/go/google.golang.org%2fgrpc/v1.82.1?slim=true) | ![confidence](https://developer.mend.io/api/mc/badges/confidence/go/google.golang.org%2fgrpc/v1.79.3/v1.82.1?slim=true) | --- ### gRPC-Go: xDS RBAC and HTTP/2 Vulnerabilities [GHSA-hrxh-6v49-42gf](GHSA-hrxh-6v49-42gf) <details> <summary>More information</summary> #### Details Multiple security vulnerabilities have been identified and addressed in grpc-go affecting the xDS RBAC authorization engine (internal/xds/rbac) and the HTTP/2 transport server implementation (internal/transport). These vulnerabilities could result in: - Authorization Bypass (Fail-Open) when translating xDS RBAC policies containing `Metadata` or `RequestedServerName` fields. - Denial of Service (High CPU Consumption) due to an HTTP/2 Rapid Reset mitigation bypass during client-initiated stream resets. - Denial of Service (Server Panic) when parsing crafted xDS RBAC policies containing `NOT` rules around unsupported fields. ##### Impact _What kind of vulnerability is it? Who is impacted?_ ##### xDS RBAC Authorization Bypass via `Metadata` & `RequestedServerName` matchers - Affected Component: xDS RBAC - Impact: When building policy matchers for gRPC RBAC from xDS configurations, unsupported `permission` and `principal` rules (specifically `Metadata` and `RequestedServerName`) were silently ignored and treated as no-ops. - If an authorization policy relied purely on these matchers for access control, treating those rules as no-ops effectively removed the restrictions. - If these unsupported rules were nested inside logical `NOT` rules (`Permission_NotRule` / `Principal_NotId`) or multi-condition `OR/AND` rules, silently dropping them changed the boolean logic flow of the authorization engine. As a result, policy evaluation decisions could fail open, allowing unauthorized clients to access protected gRPC services or resources. ##### HTTP/2 Rapid Reset Mitigation Bypass / Denial of Service via Stream Aborts - Affected Component: HTTP/2 transport - Impact: Earlier mitigations in grpc-go for HTTP/2 Rapid Reset only applied threshold checks to items that directly resulted in control frames being written back to the wire, such as `SETTINGS` ACKs or server-initiated `RST_STREAM`s. When a client initiated a rapid flood of stream creation (`HEADERS`) immediately followed by stream termination `RST_STREAM`, items queued up in the control buffer without counting against the transport response frame threshold. An attacker can repeatedly trigger this flood sequence to bypass reader blocking, resulting in high CPU usage, and Denial of Service (DoS). ##### Denial of Service (Panic) in xDS RBAC Engine via Unsupported Fields inside NOT Rules - Affected Component: xDS RBAC - Impact: The xDS RBAC policy translators recursively generate matchers for nested rules. When a `NOT` rule wrapped an unsupported or unhandled field (such as `SourcedMetadata`), the recursive step returned an empty matcher. This could result in a runtime panic when the RBAC engine attempts to authorize an incoming request. An attacker or misconfigured/malicious xDS management server delivering an LDS/RDS update containing a `NOT` rule around an unhandled field causes the gRPC server process to crash immediately (CWE-248 / Denial of Service). ##### Patches _Has the problem been patched? What versions should users upgrade to?_ All three issues have been fixed in `master` and will be released in 1.82.1 shortly. ##### Workarounds _Is there a way for users to fix or remediate the vulnerability without upgrading?_ If upgrading grpc-go immediately is not possible, apply the following workarounds based on your deployment architecture: * For xDS RBAC Vulnerabilities & Panics: Ensure that upstream xDS management servers do not push RBAC policies containing `Metadata`, `RequestedServerName`, or `NOT` rules wrapping unsupported fields (such as `SourcedMetadata`) to grpc-go servers. * For HTTP/2 Rapid Reset DOS: Configure upstream reverse proxies or load balancers (such as Envoy) with strict HTTP/2 `max_concurrent_streams` limits and active rate limiting on `RST_STREAM` frequency per connection. ##### Severity | Vulnerability | Qualitative Severity | Approximate CVSS v3.1 Score | Primary Impact | | :--- | :--- | :--- | :--- | | **xDS RBAC Authorization Bypass** | **High** | `8.2` | Unauthorized Access / Fail-Open | | **HTTP/2 Rapid Reset DOS Bypass** | **High** | `7.5` | High CPU Consumption / Denial of Service | | **xDS RBAC Engine Server Panic** | **Medium** | `5.9` | Process Crash / Denial of Service | #### Severity - CVSS Score: 8.8 / 10 (High) - Vector String: `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N` #### References - [https://github.com/grpc/grpc-go/security/advisories/GHSA-hrxh-6v49-42gf](https://github.com/grpc/grpc-go/security/advisories/GHSA-hrxh-6v49-42gf) - [https://github.com/grpc/grpc-go/pull/9236](https://github.com/grpc/grpc-go/pull/9236) - [https://github.com/grpc/grpc-go/commit/4ea465d4ab98013f72a142fe0fc89c19770b2935](https://github.com/grpc/grpc-go/commit/4ea465d4ab98013f72a142fe0fc89c19770b2935) - [https://github.com/grpc/grpc-go](https://github.com/grpc/grpc-go) - [https://github.com/grpc/grpc-go/releases/tag/v1.82.1](https://github.com/grpc/grpc-go/releases/tag/v1.82.1) This data is provided by [OSV](https://osv.dev/vulnerability/GHSA-hrxh-6v49-42gf) and the [GitHub Advisory Database](https://github.com/github/advisory-database) ([CC-BY 4.0](https://github.com/github/advisory-database/blob/main/LICENSE.md)). </details> --- ### Release Notes <details> <summary>grpc/grpc-go (google.golang.org/grpc)</summary> ### [`v1.82.1`](https://github.com/grpc/grpc-go/releases/tag/v1.82.1): Release 1.82.1 [Compare Source](grpc/grpc-go@v1.82.0...v1.82.1) ### Security - server: Stop reading from the connection when flooded by HTTP/2 frames. The default value for this limit is 100 frames, excluding DATA and HEADERS, and may be changed by setting environment variable `GRPC_GO_EXPERIMENTAL_CONTROL_BUFFER_THROTTLE_LIMIT`. - xds/rbac: Support `Metadata` and `RequestedServerName` permissions matcher fields. If present in a DENY rule, previously these would be ignored and fail-open. - xds/rbac: Fix panic when parsing unsupported fields in `NotRule`/`NotId` permissions. - xds/rbac: Support the deprecated `source_ip` principal identifier by treating it as equivalent to `direct_remote_ip`. ### [`v1.82.0`](https://github.com/grpc/grpc-go/releases/tag/v1.82.0): Release 1.82.0 [Compare Source](grpc/grpc-go@v1.81.1...v1.82.0) ### Behavior Changes - server: Remove support for `GRPC_GO_EXPERIMENTAL_DISABLE_STRICT_PATH_CHECKING` environment varibale. Strict incoming RPC path validation (which has been the default since `v1.79.3`) can no longer be disabled. ([#9112](grpc/grpc-go#9112)) - transport: Add environment variable to change the default max header list size from `16MB` to `8KB`. This may be enabled by setting `GRPC_GO_EXPERIMENTAL_ENABLE_8KB_DEFAULT_HEADER_LIST_SIZE=true`. This will be enabled by default in a subsequent release. ([#9019](grpc/grpc-go#9019)) - balancer: Load Balancing policy registry is now case-sensitive. Set `GRPC_GO_EXPERIMENTAL_CASE_SENSITIVE_BALANCER_REGISTRIES=false` (and file an issue) to revert to case-insensitive behavior. ([#9017](grpc/grpc-go#9017)) ### New Features - experimental/stats: Expose a new API, `NewContextWithLabelCallback`, to register a callback that is invoked when telemetry labels are added. ([#8877](grpc/grpc-go#8877)) - Special Thanks: [@seth-epps](https://github.com/seth-epps) - client: Return a portion of the response body in the error message, when the client receives an unexpected non-gRPC HTTP response, to make debugging easier. ([#8929](grpc/grpc-go#8929)) - Special Thanks: [@chengxilo](https://github.com/chengxilo) - server: Add environment variable `GRPC_GO_SERVER_GOROUTINE_LABELS` that controls setting `runtime/pprof.Labels` on goroutines spawned by the server. Set `GRPC_GO_SERVER_GOROUTINE_LABELS=grpc.method=true` to add the `grpc.method` label on goroutines spawned to handle incoming requests. ([#9082](grpc/grpc-go#9082)) - Special Thanks: [@dfinkel](https://github.com/dfinkel) ### Bug Fixes - xds/server: Fix a memory leak of HTTP filter instances occurring when route configurations are updated in-place during a Route Discovery Service (RDS) update. ([#9138](grpc/grpc-go#9138)) - grpc: In the deprecated `gzip` Compressor (used via the deprecated `WithCompressor` dial option), enforce the `MaxRecvMsgSize` limit on the decompressed message buffer, preventing excessive memory allocation from highly compressed payloads. ([#9114](grpc/grpc-go#9114)) - Special Thanks: [@evilgensec](https://github.com/evilgensec) - stats/opentelemetry: Record retry attempts, `grpc.previous-rpc-attempts`, at the call level and not the attempt level. ([#8923](grpc/grpc-go#8923)) - encoding: Ensure `Close()` is always called on readers returned from `Compressor.Decompress` if possible. ([#9135](grpc/grpc-go#9135)) - channelz: Fix the `LastMessageSentTimestamp` and `LastMessageReceivedTimestamp` fields in `SocketMetrics` to ensure they contain correct timestamp values. ([#9109](grpc/grpc-go#9109)) ### [`v1.81.1`](https://github.com/grpc/grpc-go/releases/tag/v1.81.1): Release 1.81.1 [Compare Source](grpc/grpc-go@v1.81.0...v1.81.1) ### Security - xds/rbac: Fix a potential authorization bypass caused by incorrectly falling through URI/DNS SANs to Subject Distinguished Name (DN) when matching the authenticated principal name. With this fix, only the first non-empty identity source will be used, as per [gRFC A41](https://github.com/grpc/proposal/blob/master/A41-xds-rbac.md). ([#9111](grpc/grpc-go#9111)) - Special Thanks: [@al4an444](https://github.com/al4an444) ### Bug Fixes - otel: Segregate client and server RPC information used for metrics and traces, to avoid one overwriting the other. ([#9081](grpc/grpc-go#9081)) ### [`v1.81.0`](https://github.com/grpc/grpc-go/releases/tag/v1.81.0): Release 1.81.0 [Compare Source](grpc/grpc-go@v1.80.0...v1.81.0) ### Behavior Changes - balancer/rls: Switch gauge metrics to asynchronous emission (once per collection cycle) to reduce telemetry noise and align with other gRPC language implementations. ([#8808](grpc/grpc-go#8808)) ### Dependencies - Minimum supported Go version is now 1.25. ([#8969](grpc/grpc-go#8969)) ### Bug Fixes - xds: Use the leaf cluster's security config for the TLS handshake instead of the aggregate cluster's config. ([#8956](grpc/grpc-go#8956)) - transport: Send a `RST_STREAM` when receiving an `END_STREAM` when the stream is not already half-closed. ([#8832](grpc/grpc-go#8832)) - xds: Fix ADS resource name validation to prevent a panic. ([#8970](grpc/grpc-go#8970)) ### New Features - grpc/stats: Add support for custom labels in per-call metrics ([gRFC A108](https://github.com/grpc/proposal/blob/master/A108-otel-custom-per-call-label.md)). ([#9008](grpc/grpc-go#9008)) - xds: Add support for Server Name Indication (SNI) and SAN validation ([gRFC A101](https://github.com/grpc/proposal/blob/master/A101-SNI-setting-and-SNI-SAN-validation.md)). Disabled by default. To enable, set `GRPC_EXPERIMENTAL_XDS_SNI=true` environment variable. ([#9016](grpc/grpc-go#9016)) - xds: Add support to control which fields get propagated from ORCA backend metric reports to LRS load reports ([gRFC A85](https://github.com/grpc/proposal/blob/master/A85-lrs-custom-metrics-changes.md)). Disabled by default. To enable, set `GRPC_EXPERIMENTAL_XDS_ORCA_LRS_PROPAGATION=true`. ([#9005](grpc/grpc-go#9005)) - xds: Add metrics to track xDS client connectivity and cached resource state ([gRFC A78](https://github.com/grpc/proposal/blob/master/A78-grpc-metrics-wrr-pf-xds.md)). ([#8807](grpc/grpc-go#8807)) - stats/otel: Enhance `grpc.subchannel.disconnections` metric by adding disconnection reason to the `grpc.disconnect_error` label ([gRFC A94](https://github.com/grpc/proposal/blob/master/A94-subchannel-otel-metrics.md)). This provides granular insights into why subchannels are closing. ([#8973](grpc/grpc-go#8973)) - mem: Add `mem.Buffer.Slice()` API to slice the buffer like a slice. ([#8977](grpc/grpc-go#8977)) - Special Thanks: [@ash2k](https://github.com/ash2k) ### Performance Improvements - alts: Pool read buffers to lower memory utilization when sockets are unreadable. ([#8964](grpc/grpc-go#8964)) - transport: Pool HTTP/2 framer read buffers to reduce idle memory consumption. Currently limited to Linux for ALTS and non-encrypted transports (TCP, Unix). To disable, set `GRPC_GO_EXPERIMENTAL_HTTP_FRAMER_READ_BUFFER_POOLING=false` and report any issues. ([#9032](grpc/grpc-go#9032)) ### [`v1.80.0`](https://github.com/grpc/grpc-go/releases/tag/v1.80.0): Release 1.80.0 [Compare Source](grpc/grpc-go@v1.79.3...v1.80.0) ### Behavior Changes - balancer: log a warning if a balancer is registered with uppercase letters, as balancer names should be lowercase. In a future release, balancer names will be treated as case-insensitive; see [#5288](grpc/grpc-go#5288) for details. ([#8837](grpc/grpc-go#8837)) - xds: update resource error handling and re-resolution logic ([#8907](grpc/grpc-go#8907)) - Re-resolve all `LOGICAL_DNS` clusters simultaneously when re-resolution is requested. - Fail all in-flight RPCs immediately upon receipt of listener or route resource errors, instead of allowing them to complete. ### Bug Fixes - xds: support the LB policy configured in `LOGICAL_DNS` cluster resources instead of defaulting to `pick_first`. ([#8733](grpc/grpc-go#8733)) - credentials/tls: perform per-RPC authority validation against the leaf certificate instead of the entire peer certificate chain. ([#8831](grpc/grpc-go#8831)) - xds: enabling A76 ring hash endpoint keys no longer causes EDS resources with invalid proxy metadata to be NACKed when HTTP CONNECT (gRFC A86) is disabled. ([#8875](grpc/grpc-go#8875)) - xds: validate that the sum of endpoint weights in a locality does not exceed the maximum `uint32` value. ([#8899](grpc/grpc-go#8899)) - Special Thanks: [@RAVEYUS](https://github.com/RAVEYUS) - xds: fix incorrect proto field access in the weighted round robin (WRR) configuration where `blackout_period` was used instead of `weight_expiration_period`. ([#8915](grpc/grpc-go#8915)) - Special Thanks: [@gregbarasch](https://github.com/gregbarasch) - xds/rbac: handle addresses with ports in IP matchers. ([#8990](grpc/grpc-go#8990)) ### New Features - ringhash: enable gRFC A76 (endpoint hash keys and request hash headers) by default. ([#8922](grpc/grpc-go#8922)) ### Performance Improvements - credentials/alts: pool write buffers to reduce memory allocations and usage. ([#8919](grpc/grpc-go#8919)) - grpc: enable the use of pooled write buffers for buffering HTTP/2 frame writes by default. This reduces memory usage when connections are idle. Use the [WithSharedWriteBuffer](https://pkg.go.dev/google.golang.org/grpc#WithSharedWriteBuffer) dial option or the [SharedWriteBuffer](https://pkg.go.dev/google.golang.org/grpc#SharedWriteBuffer) server option to disable this feature. ([#8957](grpc/grpc-go#8957)) - xds/priority: stop caching child LB policies removed from the configuration. This will help reduce memory and cpu usage when localities are constantly switching between priorities. ([#8997](grpc/grpc-go#8997)) - mem: add a faster tiered buffer pool; use the experimental [mem.NewBinaryTieredBufferPool](https://pkg.go.dev/google.golang.org/grpc/mem@master#NewBinaryTieredBufferPool) function to create such pools. ([#8775](grpc/grpc-go#8775)) </details> --- ### Configuration 📅 **Schedule**: (UTC) - Branch creation - At any time (no schedule defined) - Automerge - Between 12:00 AM and 03:59 AM (`* 0-3 * * *`) 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this PR, check this box --- This PR has been generated by [Mend Renovate](https://github.com/renovatebot/renovate).  Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/13580 Reviewed-by: Mathieu Fenniak <mfenniak@noreply.codeberg.org>

add env variable

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Pranjali-2501 added this to the 1.81 Release milestone Mar 25, 2026

Pranjali-2501 added Type: Behavior Change Behavior changes not categorized as bugs Area: Transport Includes HTTP/2 client/server and HTTP server handler transports and advanced transport features. labels Mar 25, 2026

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Pranjali-2501 merged commit e80524d into grpc:master Apr 15, 2026
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transport: set default header list size to 8KB and guard behind an env variable. - #9019

transport: set default header list size to 8KB and guard behind an env variable.#9019
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