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CVE PROGRAM SOURCE RECORD4.9 Medium

CVE-2026-9708

Incoming webhook user attribution via unvalidated webhook owner

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Status
Published
Published
Updated
Assigning organization
Mattermost

Description

Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to validate that an assigned incoming webhook user has access to the target team or channel, which allows a requester with webhook management permissions to create posts or direct messages attributed to another user via crafted incoming webhook configuration and payloads.. Mattermost Advisory ID: MMSA-2026-00683

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

  • 11.7.0 to ≤ 11.7.2affected
  • 11.6.0 to ≤ 11.6.4affected
  • 10.11.0 to ≤ 10.11.19affected
  • 11.8.0unaffected
  • 11.7.3unaffected
  • 11.6.5unaffected
  • 10.11.20unaffected

References