Improper Access Control in Mattermost for Team Admins
CVE-2025-27715

2.7LOW

Key Information:

Vendor

Mattermost
Status
Mattermost
Vendor
CVE Published:
21 March 2025

What is CVE-2025-27715?

Mattermost versions 9.11.x up to 9.11.8 contain a significant flaw in their access control mechanism. This vulnerability allows team admins to be added to private channels without their explicit approval. It enables unauthorized access when crafted permalink links are used, which undermines the privacy and security of sensitive conversations within private channels.

Affected Version(s)

Mattermost 9.11.0 <= 9.11.8

Mattermost 10.5.0

Mattermost 9.11.9

References

https://mattermost.com/security-updates

CVSS V3.1

Score:
2.7
Severity:
LOW
Confidentiality:
None
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
High
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Joram Wilander
.
CVE-2025-27715 : Improper Access Control in Mattermost for Team Admins