PT-2026-25702 · Mattermost · Mattermost

Winfunc · Published 2026-03-16 · Updated 2026-03-16 · CVE-2026-25783

NVD

CVSS v3.1

4.3

4.3

Medium

Base vector

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

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

Fix

Weakness Enumeration

CWE-1287

Related Identifiers

CVE-2026-25783

Affected Products

Mattermost

References · 3

• https://nvd.nist.gov/vuln/detail/CVE-2026-25783 · Security Note
• https://mattermost.com/security-updates · Vendor Advisory
• https://twitter.com/CVEnew/status/2033583646180053452 · Twitter Post