CVE-2026-95666

Published Sep 22, 2026

Last updated 6 days ago

Overview

Description
Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to limit the length of the post ID array accepted by the bulk reactions endpoint which allows an authenticated user to cause excessive database load via a crafted request to {{POST /api/v4/posts/ids/reactions}}.. Mattermost Advisory ID: MMSA-2026-00771
Source
responsibledisclosure@mattermost.com
NVD status
Analyzed
Products
mattermost_server

Risk scores

CVSS 3.1

Type
Secondary
Base score
4.3
Impact score
1.4
Exploitability score
2.8
Vector string
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Severity
MEDIUM

Weaknesses

responsibledisclosure@mattermost.com
CWE-770

Social media

Hype score
Not currently trending

Configurations

References

Sources include official advisories and independent security research.