CVE-2026-19867
CVE-2026-19867 · Uncapped mention keys in user notification properties allow CPU exhaustion during post processing
This page contains facts from public vulnerability sources. Check the original advisory before updating.
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
CVSS 4.3 · Medium · EPSS 0.2%
- Published
- Updated
Affected products and versions
mattermost
- Versions
- ≥ 11.10.0, ≤ 11.10.0: Affected (semver)
- ≥ 11.9.0, ≤ 11.9.1: Affected (semver)
- ≥ 11.8.0, ≤ 11.8.5: Affected (semver)
- ≥ 11.7.0, ≤ 11.7.10: Affected (semver)
- 11.11.0: Not affected
- 11.10.1: Not affected
- 11.9.2: Not affected
- 11.8.6: Not affected
- 11.7.11: Not affected
No fix published