Moole Vulnerability Database

Find real vulnerabilities before they ship

Medium

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 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

VectorNETWORK

PublishedMar 25, 2026, 17:16

Published Byresponsibledisclosure@mattermost.com

Base Score

Score6.5

Affected Versions

Package (Ecosystem)IntroducedFixedLimit

github.com/mattermost/mattermost-server(Go)11.4.0-rc111.4.1N/A

github.com/mattermost/mattermost-server(Go)11.3.0-rc111.3.2N/A

github.com/mattermost/mattermost-server(Go)11.2.0-rc111.2.4N/A

github.com/mattermost/mattermost-server(Go)10.11.0-rc110.11.12N/A

References

https://mattermost.com/security-updates

Weakness Type

CWE-400

CVSS Metrics

Base Score

6.5

Vector String

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Base SeverityMedium

Version

3.1

Attack Vector (AV)

NETWORK