CVE-2026-25783

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CVSS 3.1

4.3 medium

EPSS

<1%p21

Published

Mar 16, 2026 (Mar 16, 2026)

Modified

Jun 17, 2026

Description

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to properly validate User-Agent header tokens which allows an authenticated attacker to cause a request panic via a specially crafted User-Agent header. Mattermost Advisory ID: MMSA-2026-00586

Vendors: mattermost
Products: mattermost server
Weakness: CWE-1287
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

NVD CVE.org GitHub PoCs EPSS (0.3%)

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