VULNERABILITY INTELLIGENCE

CVE-2026-26233

CVSS score4.3 MEDIUM
EPSS probability0.31%
CISA KEVNot currently listed
Published2026-03-25
Last modified2026-06-17
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

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

Weakness classification

  • responsibledisclosure@mattermost.com: CWE-400

Primary references