Impact
Aegra deployments running 0.9.0 through 0.9.6 with multiple authenticated users on a shared instance are vulnerable to a cross-tenant IDOR. Any authenticated user (User A), given another user's thread_id (User B), can:
- Execute graph runs against User B's thread via
POST /threads/{thread_id}/runs, POST /threads/{thread_id}/runs/stream, or POST /threads/{thread_id}/runs/wait
- Read User B's full checkpoint state via the resulting run's
output field
- Inject arbitrary messages into User B's conversation history (persisted in B's checkpoint)
- Hide their activity from User B's
GET /threads/{thread_id}/runs listing because the run carries A's user_id
The streaming variant is worse — the first SSE event: values frame returns the entire prior messages array immediately on connection, no graph execution needed.
Thread IDs are UUIDs but leak through frontend URLs, server logs, observability traces, and shared links. Guessing is not required.
Patches
Fixed in 0.9.7. The three affected endpoints now perform an SQL-level user_id == authenticated_user.identity check before calling _prepare_run. When the thread exists but is owned by another user, the response is 404 Thread not found (matching the read-side pattern) to avoid leaking thread existence.
Workarounds
If upgrade is not immediately possible, register an @auth.on("threads", "create_run") handler that explicitly verifies thread ownership against the authenticated identity before allowing the operation. Without a handler, no built-in authorization runs on these write paths.
Example mitigation handler:
from langgraph_sdk import Auth
auth = Auth()
@auth.on("threads", "create_run")
async def enforce_thread_owner(ctx: Auth.types.AuthContext, value: dict):
# Look up the thread, raise 404 if not owned by ctx.user.identity.
# Implementation depends on your data layer.
...
Root cause
Aegra's authorization model delegates per-resource policy to user-defined @auth.on handlers. When no handler is registered, handle_event(...) returns None and the request proceeds (default-allow). Read endpoints in api/threads.py add a defense-in-depth user_id filter at the SQL layer, but the run-creation endpoints in api/runs.py skipped that filter. Result: out-of-the-box deployments without custom auth handlers were vulnerable.
Affected endpoints
POST /threads/{thread_id}/runs
POST /threads/{thread_id}/runs/stream
POST /threads/{thread_id}/runs/wait
Stateless variants (POST /runs, POST /runs/wait, POST /runs/stream) are NOT affected — they generate a fresh thread_id server-side and never accept a caller-supplied one.
Credits
- @JoJoTheBizarre — discovered and reported the vulnerability with a precise reproducer (#336)
- @victorjmarin and @jawhardjebbi — wrote the fix and added test coverage at unit, integration, and manual-auth e2e levels (#337)
Resources
References
Impact
Aegra deployments running 0.9.0 through 0.9.6 with multiple authenticated users on a shared instance are vulnerable to a cross-tenant IDOR. Any authenticated user (User A), given another user's
thread_id(User B), can:POST /threads/{thread_id}/runs,POST /threads/{thread_id}/runs/stream, orPOST /threads/{thread_id}/runs/waitoutputfieldGET /threads/{thread_id}/runslisting because the run carries A'suser_idThe streaming variant is worse — the first SSE
event: valuesframe returns the entire priormessagesarray immediately on connection, no graph execution needed.Thread IDs are UUIDs but leak through frontend URLs, server logs, observability traces, and shared links. Guessing is not required.
Patches
Fixed in 0.9.7. The three affected endpoints now perform an SQL-level
user_id == authenticated_user.identitycheck before calling_prepare_run. When the thread exists but is owned by another user, the response is404 Thread not found(matching the read-side pattern) to avoid leaking thread existence.Workarounds
If upgrade is not immediately possible, register an
@auth.on("threads", "create_run")handler that explicitly verifies thread ownership against the authenticated identity before allowing the operation. Without a handler, no built-in authorization runs on these write paths.Example mitigation handler:
Root cause
Aegra's authorization model delegates per-resource policy to user-defined
@auth.onhandlers. When no handler is registered,handle_event(...)returnsNoneand the request proceeds (default-allow). Read endpoints inapi/threads.pyadd a defense-in-depthuser_idfilter at the SQL layer, but the run-creation endpoints inapi/runs.pyskipped that filter. Result: out-of-the-box deployments without custom auth handlers were vulnerable.Affected endpoints
POST /threads/{thread_id}/runsPOST /threads/{thread_id}/runs/streamPOST /threads/{thread_id}/runs/waitStateless variants (
POST /runs,POST /runs/wait,POST /runs/stream) are NOT affected — they generate a freshthread_idserver-side and never accept a caller-supplied one.Credits
Resources
References