GitHub Advisoryadvisory · Go

GHSA-247x-7qw8-fp98 Mattermost doesn't rate limit login requests, allowing DoS

MEDIUM Published 2026-03-25 Modified 2026-04-06 Official page ↗
Aliases
CVE-2026-26233
Ecosystem
Go
Packages
github.com/mattermost/mattermost-server
Severity
Moderate
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Weaknesses
CWE-400
Reviewed
2026-03-31

Affected packages

• Go github.com/mattermost/mattermost-server: >= 11.4.0-rc1, < 11.4.1 → fixed in 11.4.1 • Go github.com/mattermost/mattermost-server: >= 11.3.0-rc1, < 11.3.2 → fixed in 11.3.2 • Go github.com/mattermost/mattermost-server: >= 11.2.0-rc1, < 11.2.4 → fixed in 11.2.4 • Go github.com/mattermost/mattermost-server: >= 10.11.0-rc1, < 10.11.12 → fixed in 10.11.12

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

Related

Alias · CVE (1)

  • CVE-2026-26233 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… vulnerability

Weakness · CWE (1)

  • CWE-400 Uncontrolled Resource Consumption weakness

References