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Mattermost has an Incorrect Authorization vulnerability

Low severity GitHub Reviewed Published Oct 16, 2025 to the GitHub Advisory Database • Updated Oct 16, 2025

Package

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

Affected versions

>= 10.5.0, < 10.5.11
>= 10.11.0, < 10.11.3

Patched versions

10.5.11
10.11.3
gomod github.com/mattermost/mattermost/server/v8 (Go)
< 8.0.0-20250820115038-ff30b84049f0
8.0.0-20250820115038-ff30b84049f0

Description

Mattermost versions 10.5.x <= 10.5.10, 10.11.x <= 10.11.2 fail to properly validate guest user permissions when adding channel members which allows guest users to add any team members to their private channels via the /api/v4/channels/{channel_id}/members endpoint

References

Published by the National Vulnerability Database Oct 16, 2025
Published to the GitHub Advisory Database Oct 16, 2025
Reviewed Oct 16, 2025
Last updated Oct 16, 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
None
Scope
Unchanged
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:N/S:U/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.
(4th percentile)

Weaknesses

Incorrect Authorization

The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. This allows attackers to bypass intended access restrictions. Learn more on MITRE.

CVE ID

CVE-2025-10545

GHSA ID

GHSA-424h-xj87-m937

Source code

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