CVE-2026-26233

Published Mar 25, 2026

Last updated a day ago

Overview

Description
Mattermost versions 11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11 fail to rate limit login requests which allows unauthenticated remote attackers to cause denial of service (server crash and restart) via HTTP/2 single packet attack with 100+ parallel login requests.. Mattermost Advisory ID: MMSA-2025-00566
Source
responsibledisclosure@mattermost.com
NVD status
Analyzed
Products
mattermost_server

Risk scores

CVSS 3.1

Type
Primary
Base score
6.5
Impact score
3.6
Exploitability score
2.8
Vector string
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

responsibledisclosure@mattermost.com
CWE-400

Social media

Hype score
Not currently trending

Configurations

References

Sources include official advisories and independent security research.