Vulnerability in Mattermost Product Affects Team Membership Validation
CVE-2026-2458

4.3MEDIUM

Key Information:

Vendor

Mattermost
Status
Mattermost
Vendor
CVE Published:
16 March 2026

What is CVE-2026-2458?

Certain versions of Mattermost fail to correctly validate team memberships during channel searches. This vulnerability enables a user who has been removed from a team to list all public channels available within that team, thereby exposing potentially sensitive data. Users should review updates to ensure that appropriate measures have been taken to mitigate this risk.

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Affected Version(s)

Mattermost 11.3.0

Mattermost 11.2.0 <= 11.2.2

Mattermost 10.11.0 <= 10.11.10

References

https://mattermost.com/security-updates
vendor-advisory

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

0x7oda7123
JSON
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