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CVE PROGRAM SOURCE RECORD4.3 Medium

CVE-2026-25783

Denial of service via malformed User-Agent header in getBrowserVersion

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Status
Published
Published
Updated
Assigning organization
Mattermost

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

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Mattermost Mattermost

Default version status: unaffected

  • 11.3.0 to ≤ 11.3.0affected
  • 11.2.0 to ≤ 11.2.2affected
  • 10.11.0 to ≤ 10.11.10affected
  • 11.4.0unaffected
  • 11.3.1unaffected
  • 11.2.3unaffected
  • 10.11.11unaffected

References