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CVE PROGRAM SOURCE RECORD4.3 Medium

CVE-2026-26233

Denial of Service via HTTP/2 single packet attack on login endpoint

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Status
Published
Published
Updated
Assigning organization
Mattermost

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

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

  • 11.4.0 to ≤ 11.4.0affected
  • 11.3.0 to ≤ 11.3.1affected
  • 11.2.0 to ≤ 11.2.3affected
  • 10.11.0 to ≤ 10.11.11affected
  • 11.5.0unaffected
  • 11.4.1unaffected
  • 11.3.2unaffected
  • 11.2.4unaffected
  • 10.11.12unaffected

References