Vulnerability · Published Nov 14, 2025 · Assigned by Mattermost
CVE-2025-11776Guest user can discover archived public channels
Medium 4.3
In plain English
A medium-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 0.2% (higher than 11% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)4.3Medium
Exploit odds (30 days)0.2%top 89.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Mattermost versions <11 fail to properly restrict access to archived channel search API which allows guest users to discover archived public channels via the `/api/v4/teams/{team_id}/channels/search_archived` endpoint
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/mattermost/mattermost | no fix listed | GO-2025-4126 |
| Go | github.com/mattermost/mattermost | 5.3.2-0.20250815165020-c8d66301415d | GHSA-j6gg-r5jc-47cm |
| Go | github.com/mattermost/mattermost-server | no fix listed | GO-2025-4126 |
| Go | github.com/mattermost/mattermost-server | 5.3.2-0.20250815165020-c8d66301415d | GHSA-j6gg-r5jc-47cm |
| Go | github.com/mattermost/mattermost-server/v5 | no fix listed | GO-2025-4126 |
| Go | github.com/mattermost/mattermost-server/v5 | 5.3.2-0.20250815165020-c8d66301415d | GHSA-j6gg-r5jc-47cm |
| Go | github.com/mattermost/mattermost-server/v6 | no fix listed | GO-2025-4126 |
| Go | github.com/mattermost/mattermost-server/v6 | 5.3.2-0.20250815165020-c8d66301415d | GHSA-j6gg-r5jc-47cm |
| Go | github.com/mattermost/mattermost/server/v8 | 8.0.0-20250815165020-c8d66301415d | GO-2025-4126 |
| Go | github.com/mattermost/mattermost/server/v8 | 8.0.0-20250815165020-c8d66301415d | GHSA-j6gg-r5jc-47cm |
| Go | github.com/mattermost/mattermost/v5 | no fix listed | GO-2025-4126 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mattermost | Mattermost | <11 – through <11 |
Weakness: CWE-863 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N