Vulnerability · Published Oct 16, 2025 · Assigned by Mattermost
CVE-2025-10545Guest user can add unauthorized team users to private channels
Low 3.1
In plain English
A low-severity incorrect authorization in Mattermost from Mattermost. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 27% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)3.1Low
Exploit odds (30 days)0.3%top 73.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/mattermost/mattermost-server | 10.11.3+incompatible, 10.5.11+incompatible | GO-2025-4030 |
| Go | github.com/mattermost/mattermost-server | 10.5.11 | GHSA-424h-xj87-m937 |
| Go | github.com/mattermost/mattermost-server | 10.11.3 | GHSA-424h-xj87-m937 |
| Go | github.com/mattermost/mattermost-server/v5 | no fix listed | GO-2025-4030 |
| Go | github.com/mattermost/mattermost-server/v6 | no fix listed | GO-2025-4030 |
| Go | github.com/mattermost/mattermost/server/v8 | 8.0.0-20250820115038-ff30b84049f0 | GHSA-424h-xj87-m937 |
| Go | github.com/mattermost/mattermost/server/v8 | 8.0.0-20250820115038-ff30b84049f0 | GO-2025-4030 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mattermost | Mattermost | 10.5.0 – through 10.5.1010.11.0 – through 10.11.2 |
Weakness: CWE-863 · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N