CVE-2026-19601 Mattermost CVE debrief

Who should care

System Console administrators using affected Mattermost versions should assess exposure and update their AD/LDAP connection settings to prevent potential password disclosure. They should also restrict access to the Test Connection / diagnostics feature and monitor for potential password disclosure. Affected operator, platform, vulnerability-management, and security-team impact requires verification and updates to prevent potential password disclosure.

Why it matters

CVE-2026-19601 allows System Console administrators to disclose AD/LDAP bind passwords to attacker-controlled servers. Affected Mattermost versions require verification and updates to prevent potential password disclosure.

• Potential AD/LDAP bind password disclosure to attacker-controlled servers
• Required verification of AD/LDAP connection settings and access controls
• Need for monitoring and restricting access to the Test Connection / diagnostics feature

Technical summary

Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 are vulnerable to AD/LDAP bind password disclosure due to not invalidating the stored AD/LDAP bind password when other connection settings are changed. This allows a System Console administrator to disclose the plaintext bind password to an attacker-controlled server via the Test Connection / diagnostics feature. Affected product context indicates that System Console administrators should verify and update their AD/LDAP connection settings.

Defensive priority

System Console administrators should verify and update their AD/LDAP connection settings to prevent potential password disclosure.

Recommended defensive actions

• Verify and update AD/LDAP connection settings
• Restrict access to the Test Connection / diagnostics feature
• Monitor for potential password disclosure
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and Mattermost Advisory ID MMSA-2026-00764 provide details on the vulnerability. Affected Mattermost versions require verification and updates to prevent potential password disclosure. System Console administrators should verify AD/LDAP connection settings and restrict access to the Test Connection / diagnostics feature to prevent potential password disclosure to attacker-controlled servers. Evidence limits suggest verifying AD/LDAP connection settings and access controls.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.