CVE-2026-19867
Mattermost versions 11.10.x <= 11.10.0, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10 fail to cap the number and size of mention keys stored in a user's notification properties, and to bound the quadratic multibyte-keyword matching performed for each post, which allows an authenticated user to degrade post-processing latency and consume excessive CPU on behalf of other members of any channel they share via storing an oversized notify_props.mention_keys list on their own profile.. Mattermost Advisory ID: MMSA-2026-00773
- Score
- CVSS 3.1 4.3 Medium
- Status
- Awaiting Analysis - responsibledisclosure@mattermost.com
- Published
- 2026-10-16
- Last modified
- 2026-10-16
- Weaknesses
- CWE-770
Affected products
References
- https://mattermost.com/security-updates
