CVE-2026-26233

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CVSS 3.1

6.5 medium

EPSS

<1%p23

Published

Mar 25, 2026 (Mar 25, 2026)

Modified

Jun 17, 2026

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

Vendors: mattermost
Products: mattermost server
Weakness: CWE-400
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

NVD CVE.org GitHub PoCs EPSS (0.3%)

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