Vulnerability · Published May 18, 2026 · Assigned by Mattermost
CVE-2026-6343Mattermost Playbooks Plugin fails to enforce view permissions in list endpoints, allowing unauthorized access to public playbooks
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 6% 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 94.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to check public/private permissions which allows members without these permissions to access public playbooks via /get.. Mattermost Advisory ID: MMSA-2026-00591
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/mattermost/mattermost-plugin-playbooks | 1.41.1-0.20260309184833-887d9cacb616 | GHSA-m79q-8qf5-v622 |
| Go | github.com/mattermost/mattermost-plugin-playbooks | 1.41.1-0.20260309184833-887d9cacb616 | GO-2026-5494 |
| Go | github.com/mattermost/mattermost-server | 10.11.14+incompatible, 11.4.4+incompatible, 11.5.2+incompatible | GO-2026-5494 |
| Go | github.com/mattermost/mattermost-server/v5 | no fix listed | GO-2026-5494 |
| Go | github.com/mattermost/mattermost-server/v6 | no fix listed | GO-2026-5494 |
| Go | github.com/mattermost/mattermost/server/v8 | no fix listed | GO-2026-5494 |
| Go | github.com/mattermost/mattermost/server/v8 | 11.4.4 | GHSA-m79q-8qf5-v622 |
| Go | github.com/mattermost/mattermost/server/v8 | 10.11.14 | GHSA-m79q-8qf5-v622 |
| Go | github.com/mattermost/mattermost/server/v8 | 11.5.2 | GHSA-m79q-8qf5-v622 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mattermost | Mattermost | 11.5.0 – through 11.5.110.11.0 – through 10.11.1311.4.0 – through 11.4.3 |
Weakness: CWE-863 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
References
- MMSA-2026-00591 vendor-advisory