Go/github.com/mattermost/mattermost-server CVE-2026-27656: medium 5.7, EPSS 0.18%
Mattermost allows attackers to take over arbitrary user accounts via overly permissive substring matching flaw
Action: Upgrade github.com/mattermost/mattermost-server to 10.11.12 or later.
go get github.com/mattermost/mattermost-server@v11.4.1go get github.com/mattermost/mattermost-server@v11.3.2go get github.com/mattermost/mattermost-server@v11.2.4go get github.com/mattermost/mattermost-server@v10.11.12Affected
| introduced | fixed | last affected |
|---|---|---|
| 11.4.0-rc1 | 11.4.1 | - |
| 11.3.0-rc1 | 11.3.2 | - |
| 11.2.0-rc1 | 11.2.4 | - |
| 10.11.0-rc1 | 10.11.12 | - |
Fixed versions
| 11.4.1 | 11.3.2 | 11.2.4 | 10.11.12 |
Sources
- osv: GHSA-fg35-5rf6-qg3g
- https://nvd.nist.gov/vuln/detail/CVE-2026-27656
- https://github.com/mattermost/mattermost
- https://mattermost.com/security-updates
CVE-2026-27656 · published · modified · JSON