CVE-2025-3230 in Mattermost
Summary
by MITRE • 05/30/2025
Mattermost versions 10.7.x <= 10.7.0, 10.6.x <= 10.6.2, 10.5.x <= 10.5.3, 9.11.x <= 9.11.12 fails to properly invalidate personal access tokens upon user deactivation, allowing deactivated users to maintain full system access by exploiting access token validation flaws via continued usage of previously issued tokens.
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Analysis
by VulDB Data Team • 06/08/2025
The vulnerability described in CVE-2025-3230 represents a critical authorization flaw within Mattermost server implementations across multiple version branches including 10.7.0, 10.6.2, 10.5.3, and 9.11.12. This issue stems from improper session management where the system fails to invalidate personal access tokens when user accounts are deactivated, creating a persistent security risk that undermines the fundamental principle of least privilege and account lifecycle management. The flaw specifically affects the token validation mechanism that should automatically revoke access when user accounts are no longer active, yet continues to accept valid-looking tokens from deactivated accounts.
The technical implementation of this vulnerability manifests in the authentication subsystem where personal access tokens are stored and validated without proper correlation to user account status. When administrators deactivate user accounts through standard administrative interfaces, the system should immediately invalidate all associated tokens and prevent further access attempts. However, the current implementation maintains token validity regardless of account status, allowing malicious actors or compromised accounts to continue operating with full system privileges using tokens that should have been revoked. This represents a classic case of inadequate session management and token lifecycle handling that directly violates security best practices.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass potential data breaches, privilege escalation, and persistent backdoor access within organizations relying on Mattermost for communication and collaboration. Attackers who gain access to valid personal access tokens from deactivated users can maintain continuous access to sensitive channels, files, and system configurations without detection, as the system continues to validate tokens against revoked accounts. This vulnerability particularly affects organizations with strict access control policies and those subject to compliance requirements such as SOC 2, ISO 27001, and GDPR, where unauthorized access to communication systems represents a significant regulatory and operational risk.
Organizations should implement immediate mitigations including manual token revocation procedures for all deactivated accounts, enhanced monitoring of token usage patterns, and implementation of automated token lifecycle management processes. The vulnerability aligns with CWE-613 and CWE-306 categories related to inadequate session management and improper access control, while also mapping to ATT&CK techniques such as T1566 for credential access and T1078 for valid accounts. System administrators should conduct comprehensive audits of all active tokens and implement automated token expiration policies with regular review cycles. Additionally, organizations should consider implementing multi-factor authentication requirements for token usage and establish protocols for immediate token revocation upon user deactivation to prevent similar vulnerabilities in other authentication systems.