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CVE PROGRAM SOURCE RECORD6.5 Medium

CVE-2026-19541

Outgoing OAuth connection client secret exposure during connection validation

Description

Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to require re-entry of the stored client secret when validating an outgoing OAuth connection, which allows an authenticated user with permission to manage outgoing OAuth connections to obtain the secret via pointing the token URL at an attacker-controlled endpoint and triggering validation.. Mattermost Advisory ID: MMSA-2026-00761

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

  • 11.9.0 to ≤ 11.9.1affected
  • 11.8.0 to ≤ 11.8.5affected
  • 11.7.0 to ≤ 11.7.10affected
  • 11.10.0 to ≤ 11.10.1affected
  • 11.11.0unaffected
  • 11.9.2unaffected
  • 11.8.6unaffected
  • 11.7.11unaffected
  • 11.10.2unaffected

References