Mattermost up to 10.11.22/11.7.7/11.8.4/11.9.0 Data Retention Teams Endpoint policies privileges management

Summaryinfo

A vulnerability was found in Mattermost up to 10.11.22/11.7.7/11.8.4/11.9.0. It has been rated as critical. The impacted element is an unknown function of the file /api/v4/data_retention/policies of the component Data Retention Teams Endpoint. This manipulation causes privileges management. This vulnerability is registered as CVE-2026-91181. Remote exploitation of the attack is possible. No exploit is available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as critical was found in Mattermost up to 10.11.22/11.7.7/11.8.4/11.9.0. Affected by this vulnerability is an unknown function of the file /api/v4/data_retention/policies of the component Data Retention Teams Endpoint. The manipulation with an unknown input leads to a privileges management vulnerability. The CWE definition for the vulnerability is CWE-269. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 Fail to sanitize Team objects returned by the data retention teams endpoint which allows an authenticated user holding only the read-only Data Retention Policy permission to obtain a private team's secret invite_id and email, and use it to join the team without authorization, via GET /api/v4/data_retention/policies/{policy_id}/teams.. Mattermost Advisory ID: MMSA-2026-00702

It is possible to read the advisory at mattermost.com. This vulnerability is known as CVE-2026-91181 since 09/14/2026. The exploitation appears to be easy. The attack can be launched remotely. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1068 according to MITRE ATT&CK.

Upgrading to version 10.11.23, 11.7.8, 11.8.5, 11.9.1 or 11.10.0 eliminates this vulnerability.

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Productinfo

Type

• Groupware Software

Name

• Mattermost

Version

• 10.11.0
• 10.11.1
• 10.11.2
• 10.11.3
• 10.11.4
• 10.11.5
• 10.11.6
• 10.11.7
• 10.11.8
• 10.11.9
• 10.11.10
• 10.11.11
• 10.11.12
• 10.11.13
• 10.11.14
• 10.11.15
• 10.11.16
• 10.11.17
• 10.11.18
• 10.11.19
• 10.11.20
• 10.11.21
• 10.11.22
• 11.0
• 11.1
• 11.2
• 11.3
• 11.4
• 11.5
• 11.6
• 11.7
• 11.7.0
• 11.7.1
• 11.7.2
• 11.7.3
• 11.7.4
• 11.7.5
• 11.7.6
• 11.7.7
• 11.8
• 11.8.0
• 11.8.1
• 11.8.2
• 11.8.3
• 11.8.4
• 11.9.0

License

• open-source

CPE 2.3info

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CPE 2.2info

• 🔒
• 🔒
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