CVE-2026-19867

MediumCVSS 4.3/10Last modified Oct 29, 2026

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

Metrics

CVSS 3.1 4.3/10CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

Weakness enumeration

CWE-770

Affected software

Vendor	Product	Versions
Mattermost	Mattermost	>= 11.10.0, <= 11.10.0; >= 11.9.0, <= 11.9.1; >= 11.8.0, <= 11.8.5; >= 11.7.0, <= 11.7.10

References

https://mattermost.com/security-updatesVendor Advisory

Timeline

Published: Oct 16, 2026
Last modified: Oct 29, 2026
NVD status: Analyzed

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