CVE-2026-26233

MEDIUM

4.3

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

CVE Details

CVSS v3.1 Score4.3

SeverityMEDIUM

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

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredLOW

User InteractionNONE

Published3/25/2026

Last Modified3/26/2026

Sourcenvd

Honeypot Sightings0

Affected Products

mattermost:mattermost_server

Weaknesses (CWE)

CWE-400

References

https://mattermost.com/security-updates(responsibledisclosure@mattermost.com)

IOC Correlations

No correlations recorded

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