CVE-2025-31947
Mattermost Server 9.11.0 – 9.11.12
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:LCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2025-31947 is a medium-severity Overly Restrictive Account Lockout Mechanism (CWE-645) vulnerability in Mattermost Mattermost Server. Its CVSS base score is 5.8 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Account Access Removal (T1531); ranked at the 26th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to AC-7 (Unsuccessful Logon Attempts) — see the control section below for these in your framework.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-15150
Vulnerability Data
Mattermost versions 10.6.x <= 10.6.1, 10.5.x <= 10.5.2, 10.4.x <= 10.4.4, 9.11.x <= 9.11.11 fail to lockout LDAP users following repeated login failures, which allows attackers to lock external LDAP accounts through repeated login failures through Mattermost.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Properly tuned thresholds and lock durations in the unsuccessful logon control stop an overly sensitive lockout from being introduced or exploited for DoS.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Credential management policies directly govern lockout thresholds and reset procedures.
Authentication policies include lockout parameters that must not be overly restrictive.
Authorization policy definition and review encompass account lockout rules and exceptions.
Monitoring can detect resulting lockouts but does not prevent an overly restrictive mechanism.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Access control policy should define lockout thresholds and recovery procedures to avoid overly restrictive denial-of-service.
Authentication information management includes setting lockout parameters that balance security against accidental lockouts.
Access rights administration must include procedures for unlocking accounts and reviewing lockout events.
Secure authentication mechanisms directly specify lockout thresholds, unlock processes, and monitoring to prevent abuse.