Description
Mattermost versions 10.5.x <= 10.5.10, 10.11.x <= 10.11.2 fail to properly validate guest user permissions when adding channel members which allows guest users to add any team members to their private channels via the `/api/v4/channels/{channel_id}/members` endpoint
Metrics
CVSS 3.1 4.3/10
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:NWeakness enumeration
Affected software
| Vendor | Product | Versions |
|---|---|---|
| Mattermost | Mattermost | >= 10.5.0, <= 10.5.10; >= 10.11.0, <= 10.11.2 |
References
- https://mattermost.com/security-updatesVendor Advisory
Timeline
- Published
- Oct 16, 2025
- Last modified
- Oct 19, 2026
- NVD status
- Analyzed