Go/github.com/mattermost/mattermost-server/v6 CVE-2026-5740: high 7.5, EPSS 0.34%
Mattermost doesn't properly validate msgpack-encoded WebSocket frames before memory allocation in github.com/mattermost/mattermost-server
Action: No fix published. Pin and monitor.
Affected
| introduced | fixed | last affected |
|---|---|---|
| 0 | - | - |
Fixed versions
No fixed version in the source.
Sources
- osv: GO-2026-5838#Go/github.com/mattermost/mattermost-server/v6
- nvd: CVE-2026-5740
- https://github.com/advisories/GHSA-w9m8-p4cc-4qj9
- https://github.com/mattermost/mattermost/commit/17939826efa20a97f087b3d390ec5136df350bae
- https://mattermost.com/security-updates
CVE-2026-5740 · published · modified · JSON