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Mattermost allows other users to determine when users had read channels via channel member objects

Low severity GitHub Reviewed Published Nov 18, 2025 to the GitHub Advisory Database • Updated Nov 27, 2025

Package

gomod github.com/mattermost/mattermost-server (Go)

Affected versions

>= 10.11.0, < 10.11.4
>= 10.5.0, < 10.5.12

Patched versions

10.11.4
10.5.12
gomod github.com/mattermost/mattermost/server/v8 (Go)
< 8.0.0-20250905150616-ba86dfc5876b6
8.0.0-20250905150616-ba86dfc5876b6

Description

Mattermost versions 10.11.x <= 10.11.3, and 10.5.x <= 10.5.11 fail to enforce access permissions on the Agents plugin which allows other users to determine when users had read channels via channel member objects.

References

Published by the National Vulnerability Database Nov 18, 2025
Published to the GitHub Advisory Database Nov 18, 2025
Reviewed Nov 18, 2025
Last updated Nov 27, 2025

Severity

Low

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
Low
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:N/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(8th percentile)

Weaknesses

Incorrect Default Permissions

During installation, installed file permissions are set to allow anyone to modify those files. Learn more on MITRE.

CVE ID

CVE-2025-55074

GHSA ID

GHSA-9hh7-6558-qfp2

Source code

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