Sensitive Credential Exposure in Mattermost by Mattermost
CVE-2026-6346

8.7HIGH

Key Information:

Vendor

Mattermost
Status
Mattermost
Vendor
CVE Published:
18 May 2026

What is CVE-2026-6346?

Mattermost versions 11.5.x up to 11.5.1, 10.11.x up to 10.11.13, and 11.4.x up to 11.4.3 are affected by a vulnerability that fails to properly sanitize sensitive configuration fields included in generated support packets. This oversight can enable a Mattermost System Administrator, or anyone with access to a support packet, to potentially extract sensitive credentials in plaintext, leading to severe security risks. For more details, refer to the Mattermost Security Advisory.

Affected Version(s)

Mattermost 11.5.0 <= 11.5.1

Mattermost 10.11.0 <= 10.11.13

Mattermost 11.4.0 <= 11.4.3

References

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

CVSS V3.1

Score:
8.7
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
High
User Interaction:
None
Scope:
Changed

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Edgar Bellot MicĂł
.