Vulnerability · Published Aug 17, 2026 · Assigned by Mattermost
CVE-2026-16048Channel member roles accept out-of-scope roles
Medium 6.3
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 0.3% (higher than 18% of all known vulnerabilities).
Severity (CVSS 3.1)6.3Medium
Exploit odds (30 days)0.3%top 82.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Mattermost versions 11.8.x <= 11.8.2, 11.7.x <= 11.7.6, 10.11.x <= 10.11.21 fail to restrict channel member role assignment to channel-scoped roles which allows a channel administrator to gain additional channel permissions via the channel member roles API.. Mattermost Advisory ID: MMSA-2026-00697
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mattermost | Mattermost | 11.8.0 – through 11.8.211.7.0 – through 11.7.610.11.0 – through 10.11.21 |
Weakness: CWE-863 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
References
- MMSA-2026-00697 vendor-advisory