CVE-2025-13352

Mattermost GitHub Plugin allows unauthorized GitHub reactions via reaction forwarding hijacking

CVSS 3 LOWEPSS 0.1%CWE-1287

Vexday Risk Score

8Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 3EPSS 0.1%KEV nãoPoC —Nuclei —Metasploit —Patch —

Lifecycle

17 Dec 2025Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

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.

CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:N/I:L/A:N

Affected products

Mattermost · Mattermost

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References

https://mattermost.com/security-updates