CVE-2026-19603
CVE-2026-19603 · Private channel ID disclosure via user status endpoints
This page contains facts from public vulnerability sources. Check the original advisory before updating.
Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to sanitize the active channel field returned by the user status API endpoints, which allows an authenticated user to learn the channel ID of a private channel another user is actively viewing via the status endpoints, without being a member of that channel. Mattermost Advisory ID: MMSA-2026-00765
CVSS 4.3 · Medium · EPSS 0.2%
- Published
- Updated
Affected products and versions
mattermost
- Versions
- ≥ 11.9.0, ≤ 11.9.1: Affected (semver)
- ≥ 11.8.0, ≤ 11.8.5: Affected (semver)
- ≥ 11.7.0, ≤ 11.7.10: Affected (semver)
- ≥ 11.10.0, ≤ 11.10.1: Affected (semver)
- 11.11.0: Not affected
- 11.9.2: Not affected
- 11.8.6: Not affected
- 11.7.11: Not affected
- 11.10.2: Not affected
No fix published