Mattermost 10.11.19-11.7.2: Unsanitized Team Objects Privileged API Access
CVE-2026-9820 Published on July 13, 2026
Mattermost schemes teams endpoint exposes private team invite IDs
Mattermost versions 11.7.x <= 11.7.2, 10.11.x <= 10.11.19 fail to sanitize team objects returned by the scheme teams endpoint, which allows a user with the User Manager role to obtain invite links for private teams and use them to join or share access to those teams via the scheme teams API endpoint.. Mattermost Advisory ID: MMSA-2026-00671
Vulnerability Analysis
CVE-2026-9820 is exploitable with network access, and requires user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a small impact on confidentiality and integrity, and no impact on availability.
Weakness Type
What is an AuthZ Vulnerability?
The software does not perform an authorization check when an actor attempts to access a resource or perform an action.
CVE-2026-9820 has been classified to as an AuthZ vulnerability or weakness.
Products Associated with CVE-2026-9820
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Affected Versions
Mattermost:- Version 11.7.0, <= 11.7.2 is affected.
- Version 10.11.0, <= 10.11.19 is affected.
- Version 11.8.0 is unaffected.
- Version 11.7.3 is unaffected.
- Version 10.11.20 is unaffected.