Go/github.com/mattermost/mattermost-server CVE-2026-5740: high 7.5, EPSS 0.34%
Mattermost doesn't properly validate msgpack-encoded WebSocket frames before memory allocation
Action: Upgrade github.com/mattermost/mattermost-server to 10.11.15 or later.
go get github.com/mattermost/mattermost-server@v11.6.1go get github.com/mattermost/mattermost-server@v11.5.4go get github.com/mattermost/mattermost-server@v11.4.5go get github.com/mattermost/mattermost-server@v10.11.15Affected
| introduced | fixed | last affected |
|---|---|---|
| 11.6.0 | 11.6.1 | - |
| 11.5.0 | 11.5.4 | - |
| 11.4.0 | 11.4.5 | - |
| 10.11.0 | 10.11.15 | - |
Fixed versions
| 11.6.1 | 11.5.4 | 11.4.5 | 10.11.15 |
Sources
- osv: GHSA-w9m8-p4cc-4qj9
- https://nvd.nist.gov/vuln/detail/CVE-2026-5740
- https://github.com/mattermost/mattermost/commit/17939826efa20a97f087b3d390ec5136df350bae
- https://github.com/mattermost/mattermost
- https://mattermost.com/security-updates
CVE-2026-5740 · published · modified · JSON