CVE-2025-53971 json
Channel and Team Membership APIs inadvertently allow loss of Member privileges.
published 2025-08-21 14 mo ago modified 2026-06-17 4 mo ago also GHSA-4276-cm8c-788h , GO-2025-3902 , EUVD-2025-25413
- cvss
- 3.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 10%
- public exploits
- 0
- none known
Summary
Mattermost versions 10.5.x <= 10.5.8, 9.11.x <= 9.11.17 fail to properly validate authorization for team scheme role modifications which allows Team Admins to demote Team Members to Guests via the PUT /api/v4/teams/team-id/members/user-id/schemeRoles API endpoint.
Patch / fix
- go github.com/mattermost/mattermost-server 9.11.18, 9.11.18+incompatible, 10.5.9, 10.5.9+incompatible
- go github.com/mattermost/mattermost/server/v8 8.0.0-20250721095846-c602a4a78e1f
- Mattermost Mattermost 9.11.18, 10.5.9, 10.10.0
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 14 mo ago
Exploit prediction
0.20% chance of exploitation in the next 30 days, higher than 10% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 3.8 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N |
| GitHub | 3.1 | 3.8 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| go | github.com/mattermost/mattermost-server | >=10.5.0, <10.5.9 >=9.11.0, <9.11.18 >=9.11.0+incompatible, <9.11.18+incompatible >=10.5.0+incompatible, <10.5.9+incompatible |
10.5.9 9.11.18 9.11.18+incompatible 10.5.9+incompatible |
| go | github.com/mattermost/mattermost/server/v8 | <8.0.0-20250721095846-c602a4a78e1f |
8.0.0-20250721095846-c602a4a78e1f |
| go | github.com/mattermost/mattermost-server/v5 | <=5.39.3 all versions |
no fix listed |
| go | github.com/mattermost/mattermost-server/v6 | <=6.7.2 all versions |
no fix listed |
Affected products
- Mattermost Mattermost
Classification
- Weakness
-
- CWE-863 Incorrect Authorization
References
-
mattermost.com
/security-updates
web, vendor-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2025-53971
advisory
-
github.com
/mattermost/mattermost
package
-
pkg.go.dev
/vuln/GO-2025-3902
web
-
github.com
/advisories/GHSA-4276-cm8c-788h
advisory
Sources
- CVE List CVE-2025-53971
- GitHub Advisory GHSA-4276-cm8c-788h
- NVD CVE-2025-53971
- OSV GO-2025-3902
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.