CVE-2025-25068 in Mattermost
Summary
by MITRE • 03/21/2025
Mattermost versions 10.4.x <= 10.4.2, 10.3.x <= 10.3.3, 9.11.x <= 9.11.8, 10.5.x <= 10.5.0 fail to enforce MFA on plugin endpoints, which allows authenticated attackers to bypass MFA protections via API requests to plugin-specific routes.
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Analysis
by VulDB Data Team • 03/28/2025
The vulnerability identified as CVE-2025-25068 represents a critical authentication bypass flaw in Mattermost server implementations across multiple version branches including 10.4.x through 10.4.2, 10.3.x through 10.3.3, 9.11.x through 9.11.8, and 10.5.x through 10.5.0. This issue stems from the improper enforcement of multi-factor authentication mechanisms specifically for plugin endpoints within the Mattermost platform. The flaw allows authenticated attackers who have already established a valid session to circumvent mandatory multi-factor authentication requirements when accessing plugin-specific API routes.
The technical implementation of this vulnerability demonstrates a failure in the security architecture's privilege validation mechanisms. When users authenticate to Mattermost, the system correctly establishes their identity and session context. However, the platform fails to properly validate whether multi-factor authentication has been completed before granting access to plugin endpoints that should require additional security layers. This creates a scenario where attackers who have already authenticated can exploit the system's inconsistent enforcement of MFA policies to access sensitive plugin functionality without the required second factor authentication.
The operational impact of this vulnerability extends beyond simple access control bypasses and represents a significant risk to organizations relying on Mattermost for secure communication and collaboration. Attackers can leverage this flaw to execute unauthorized actions through plugin interfaces, potentially gaining access to sensitive data, modifying system configurations, or performing administrative functions that should require additional authentication layers. The vulnerability affects the core security model of the platform, undermining the security controls that organizations depend upon to protect their communication infrastructure.
This vulnerability maps directly to CWE-305 Authentication Bypass by Multiple Factors, which specifically addresses scenarios where systems fail to properly enforce multi-factor authentication requirements. The flaw also aligns with ATT&CK technique T1078 Valid Accounts, as it allows attackers to leverage legitimate authenticated sessions to bypass additional security controls. From a broader security perspective, this represents a failure in the principle of least privilege and demonstrates inadequate separation of concerns in the authentication enforcement mechanisms.
Organizations should immediately implement mitigations including updating to patched versions of Mattermost where available, implementing additional network-level controls to restrict access to plugin endpoints, and conducting thorough security audits of their Mattermost configurations. The recommended approach involves enforcing strict access controls at the API level, implementing additional authentication checks for plugin endpoints, and monitoring for unauthorized access attempts to plugin-specific routes. Security teams should also consider implementing network segmentation and additional monitoring controls to detect potential exploitation attempts of this vulnerability.