CVE-2025-13352 Mattermost GitHub Plugin allows unauthorized GitHub reactions via reaction forwarding hijacking
Attackers can hijack GitHub reaction features to force users to add reactions to arbitrary GitHub objects via crafted notification posts.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2025-13352?
CVE-2025-13352 is a low-severity missing authorization vulnerability in Mattermost Mattermost Server, published on 17 Dec 2025. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official 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.
Weakness: CWE-1287
Which versions are affected by CVE-2025-13352?
14 open source packages ship an affected version, including github.com/mattermost/mattermost/server/v8, github.com/mattermost/mattermost and github.com/mattermost/mattermost-plugin-github. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/mattermost/mattermost/server/v8 Go | All versions | None |
github.com/mattermost/mattermost/server/v8 Go | From 10.11.0-rc1 | 10.11.7-0.20251106103514-3b05384dd014 |
github.com/mattermost/mattermost/server/v8 Go | From 10.11.0-rc1 | 10.11.7-0.20251106103514-3b05384dd014 |
github.com/mattermost/mattermost Go | All versions | 10.11.7-0.20251106103514-3b05384dd014 |
github.com/mattermost/mattermost Go | All versions | 10.11.7-0.20251106103514-3b05384dd014 |
github.com/mattermost/mattermost Go | From 11.0.0-alpha.1 | 11.1.0 |
8 more packages
github.com/mattermost/mattermost Go | From 11.0.0-alpha.1 | 11.1.0 |
github.com/mattermost/mattermost Go | From 11.0.0-alpha.1+incompatible | 11.1.0+incompatible |
github.com/mattermost/mattermost-plugin-github Go | All versions | 1.0.1-0.20250829075715-0deffcfc6bee |
github.com/mattermost/mattermost-plugin-github Go | All versions | 1.0.1-0.20250829075715-0deffcfc6bee |
github.com/mattermost/mattermost-plugin-github Go | All versions | 1.0.1-0.20250829075715-0deffcfc6bee |
github.com/mattermost/mattermost-server Go | From 10.11.0-rc1+incompatible | None |
github.com/mattermost/mattermost-server/v5 Go | All versions | None |
github.com/mattermost/mattermost-server/v6 Go | All versions | None |
Products include Mattermost Mattermost Server.
How do I fix CVE-2025-13352?
Upgrade github.com/mattermost/mattermost/server/v8 to 10.11.7-0.20251106103514-3b05384dd014 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2025-13352 being exploited?
There is no known exploitation of CVE-2025-13352 in the wild and no public exploit code.
Other vulnerabilities in Mattermost Mattermost Server
- CVE-2025-12419 Account takeover on OAuth/OpenID-enabled servers
- CVE-2025-12421 Account Takeover via Code Exchange Endpoint
- CVE-2025-4981 Path Traversal Leading to RCE by Any Authenticated Mattermost User
- CVE-2025-20051 Arbitrary file read via block duplication in Mattermost Boards
- CVE-2025-25279 Arbitrary file read in Mattermost Boards via import & export board archive
Sources
Also known as GHSA-jf5h-xfw4-p8gp, GO-2025-4247.