CVE-2025-13352

Mattermost GitHub Plugin allows unauthorized GitHub reactions via reaction forwarding hijacking

Published Dec 17, 2025 CVSS 3.1 · 3 Low EPSS < 1% KEV · Not listed
Description
Mattermost versions 10.11.x <= 10.11.6 and Mattermost GitHub plugin versions <=2.4.0 fail to validate plugin bot identity in reaction forwarding which allows attackers to hijack the GitHub reaction feature to make users add reactions to arbitrary GitHub objects via crafted notification posts.

Remediation

Vendor Solution

Update Mattermost to versions 11.1.0, 10.11.7 or higher. Alternatively, update the Mattermost GitHub plugin to version 2.5.0 or higher.

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-jf5h-xfw4-p8gp Mattermost GitHub Plugin Bot Identity Validation Bypass Allows Arbitrary GitHub Reaction Injection
References
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Mattermost mattermost Server
CPEs cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
Vendors & Products Mattermost mattermost Server
Type Values Removed Values Added
First Time appeared Mattermost
Mattermost mattermost
Vendors & Products Mattermost
Mattermost mattermost
Type Values Removed Values Added
Description Mattermost versions 10.11.x <= 10.11.6 and Mattermost GitHub plugin versions <=2.4.0 fail to validate plugin bot identity in reaction forwarding which allows attackers to hijack the GitHub reaction feature to make users add reactions to arbitrary GitHub objects via crafted notification posts.
Title Mattermost GitHub Plugin allows unauthorized GitHub reactions via reaction forwarding hijacking
Weaknesses CWE-1287
References
Metrics cvssV3_1

{'score': 3, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:N/I:L/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Mattermost
Published
Updated
Dec 17, 2025, 4:48 PM
Reserved
Nov 18, 2025, 10:07 AM
Status
Analyzed
Published
Dec 17, 2025, 1:15 PM
Modified
Oct 13, 2026, 11:10 AM