Vulnerability · Published Jul 13, 2026 · Assigned by Mattermost
CVE-2026-9820Mattermost schemes teams endpoint exposes private team invite IDs
Low 3.8
In plain English
A low-severity missing authorization in Mattermost from Mattermost. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 17% of all known vulnerabilities).
Severity (CVSS 3.1)3.8Low
Exploit odds (30 days)0.3%top 82.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
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
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mattermost | Mattermost | 11.7.0 – through 11.7.210.11.0 – through 10.11.19 |
Weakness: CWE-862 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N
References
- MMSA-2026-00671 vendor-advisory