CVE-2026-91181 Data Retention Teams Endpoint Leaks Private Team Invite ID
Authenticated users with read-only data retention permissions can leak private team invite IDs and emails, allowing unauthorized team access.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-91181?
CVE-2026-91181 is a medium-severity vulnerability in Mattermost Mattermost Server, published on 14 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Official description
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
Weakness: CWE-863
Which versions are affected by CVE-2026-91181?
It affects 1 product.
Products include Mattermost Mattermost Server.
How do I fix CVE-2026-91181?
Apply the vendor's patch.
Is CVE-2026-91181 being exploited?
There is no known exploitation of CVE-2026-91181 in the wild and no public exploit code.
Other vulnerabilities in Mattermost Mattermost Server
- CVE-2025-12419 Account takeover on OAuth/OpenID-enabled servers
- CVE-2025-12421 Account Takeover via Code Exchange Endpoint
- CVE-2025-4981 Path Traversal Leading to RCE by Any Authenticated Mattermost User
- CVE-2025-20051 Arbitrary file read via block duplication in Mattermost Boards
- CVE-2025-25279 Arbitrary file read in Mattermost Boards via import & export board archive
Sources
Also known as GHSA-w86c-vmwh-pppx, MINI-36q3-vq87-4v6r, MINI-8xmr-q683-3xm3.