CVE-2026-26233CWE-400

Denial of Service via HTTP/2 single packet attack on login endpoint

Medium · published March 25, 2026

CVSS v3.1
4.3
EPSS
1%
Percentile
44.9
In the wild
Unconfirmed
What it is

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

The record
Technical detail
CVSS v3.1
4.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
CVSS v4.0
Not supplied
EPSS
0.00544 · 44.9th percentile
Weakness
CWE-400 · Uncontrolled Resource Consumption
Published
2026-03-25T16:24Z
EPSS history
Timeline
  • 25 MAR 16:24Z
    Denial of Service via HTTP/2 single packet attack on login endpoint
    cvelistv5