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 t...

EUVD-2026-102808

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 t...

CVE-2026-19867

Mattermost versions 11.10.x <= 11.10.0 , 11.9.x <= 11.9.1 , 11.8.x <= 11.8.5 , and 11.7.x

CVE-2026-19867 Uncapped mention keys in user notification properties allow CPU exhaustion during post processing

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 t...

CVE-2026-19867 Uncapped mention keys in user notification properties allow CPU exhaustion during post processing

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 t...

CVE-2026-19867 Uncapped mention keys in user notification properties allow CPU exhaustion during post processing

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 t...

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 t...

CVE-2026-19867: Allocation of Resources Without Limits or Throttling

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 t...

Mattermost resource management error vulnerability

Mattermost versions 11.10.0 and earlier of 11.10.x series, 11.9.1 and earlier of 11.9.x series, 11.8.5 and earlier of 11.8.x series, and 11.7.10 and earlier of 11.7.x series have a resource management vulnerability. This vulnerability arises from failing to limit the number and size of mentionkey...