CVE-2026-19867
MEDIUM
CVSS 4.3
Published: 2026-10-16
Modified: 2026-10-16
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Description
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
Quick Facts
| CVE ID | CVE-2026-19867 |
| CVSS Score | 4.3 |
| Vector | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L |
| Published | 2026-10-16 |
| Exploited | No |
| CISA KEV | No |
| PoC | Not public |