CVE-2026-25783 — Denial of service via malformed User-Agent header in getBrowserVersion

CVE-2026-25783

Denial of service via malformed User-Agent header in getBrowserVersion PUBLISHED

Description (CNA)

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

Affected (CNA)

Vendor / product	Versions
Mattermost / Mattermost	affected 11.3.0 through 11.3.0; affected 11.2.0 through 11.2.2; affected 10.11.0 through 10.11.10; unaffected 11.4.0; unaffected 11.3.1; unaffected 11.2.3; unaffected 10.11.11

CWE

CWE-1287

References

https://mattermost.com/security-updates

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.