CVE-2025-13352 | Mattermost GitHub Plugin allows unauthorized GitHub reactions via reaction forwarding hijacking

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.

Published: 2025-12-17 Last update: 2025-12-29 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-13352 is rated Low Risk (17.8/100): CVSS Low severity, with low exploitation likelihood (EPSS 0.05%). Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-13352

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-27 0.05% 0.05% +0.01%
2 2026-05-15 0.05% 0.05% -0.01%
3 2026-01-18 — 0.05% —

Full EPSS history (4 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-13352

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
3.0 3.1 LOW
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:N/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 1.3 1.4 [email protected]

Weakness enumeration for CVE-2025-13352

GitHub Security Advisory for CVE-2025-13352

GHSA-jf5h-xfw4-p8gp · Severity: low · Ecosystem: go — Mattermost GitHub Plugin Bot Identity Validation Bypass Allows Arbitrary GitHub Reaction Injection

Affected software / configurations for CVE-2025-13352

Vendor Product Version Raw CPE
mattermost mattermost_server >= 10.11.0, < 10.11.7 cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*

References for CVE-2025-13352

URL Tags
https://mattermost.com/security-updates Vendor Advisory
cvelogic Threat Intelligence