Go/github.com/mattermost/mattermost-server CVE-2026-5163: medium 6.5, EPSS 0.21%
Mattermost doesn't verify channel membership when processing AI-assisted message rewrites
Action: Upgrade github.com/mattermost/mattermost-server to 5.3.2-0.20260401090745-f4d1abe7e8f5 or later.
go get github.com/mattermost/mattermost-server@v5.3.2-0.20260401090745-f4d1abe7e8f5Affected
| introduced | fixed | last affected |
|---|---|---|
| 0 | 5.3.2-0.20260401090745-f4d1abe7e8f5 | - |
Fixed versions
| 5.3.2-0.20260401090745-f4d1abe7e8f5 |
Sources
- osv: GHSA-8r89-8w26-cq32#Go/github.com/mattermost/mattermost-server
- https://nvd.nist.gov/vuln/detail/CVE-2026-5163
- https://github.com/mattermost/mattermost/commit/f4d1abe7e8f545f1a87f463fa9fe451c731aebf8
- https://github.com/mattermost/mattermost
- https://mattermost.com/security-updates
CVE-2026-5163 · published · modified · JSON