Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail prevent disclosure of created user password which allows a malicious attacker to impersonate a user via the use of some of those passwords.. Mattermost Advisory ID: MMSA-2026-00614
CVE-2026-6345
MEDIUMNVD 6.56.5—
EchelonGraph scoreHIGH confidence
Score 6.5 from GitHub Security Advisory published 2026-05-18. NVD baseline CVSS 6.5; sources differ by 0.0.
Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
6.5
- CVSS v3
- 6.5
- EG Score
- 6.5(high)
- EPSS
- 8.2%
- KEV
- Not listed
Published
May 18, 2026
Last Modified
May 18, 2026
References (1)
- responsibledisclosure@mattermosthttps://mattermost.com/security-updates
Frequently asked(5)
What is CVE-2026-6345?
CVE-2026-6345 is a medium vulnerability published on May 18, 2026. Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail prevent disclosure of created user password which allows a malicious attacker to impersonate a user via the use of some of those passwords.. Mattermost Advisory ID: MMSA-2026-00614
When was CVE-2026-6345 disclosed?
CVE-2026-6345 was first published in the National Vulnerability Database on May 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-6345 actively exploited?
CVE-2026-6345 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 8.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-6345?
CVE-2026-6345 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-6345?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-6345, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-6345
Is Your Infrastructure Affected by CVE-2026-6345?
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