Access Control Vulnerability in Mattermost Affecting Guest User Permissions
CVE-2025-11776

4.3MEDIUM

Key Information:

Vendor

Mattermost
Status
Mattermost
Vendor
CVE Published:
14 November 2025

What is CVE-2025-11776?

Mattermost versions prior to 11 expose a vulnerability where the archived channel search API does not adequately restrict access for guest users. This flaw allows unauthorized individuals to discover archived public channels through the endpoint /api/v4/teams/{team_id}/channels/search_archived, posing a risk to data confidentiality and privacy within the platform.

Affected Version(s)

Mattermost <11 <= 11

Mattermost 11.0.0

References

https://mattermost.com/security-updates

CVSS V3.1

Score:
4.3
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
None
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

lordwillmore
JSON
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CVE-2025-11776 : Access Control Vulnerability in Mattermost Affecting Guest User Permissions