CVE-2025-46702 in Mattermost
Summary
by MITRE • 06/30/2025
Mattermost versions 10.5.x <= 10.5.5, 9.11.x <= 9.11.15, 10.8.x <= 10.8.0, 10.7.x <= 10.7.2, 10.6.x <= 10.6.5 fail to properly enforce channel member management permissions when adding participants to playbook runs. This allows authenticated users with member-level permissions to bypass system admin restrictions and add or remove users to/from private channels via the playbook run participants feature, even when the 'Manage Members' permission has been explicitly removed. This can lead to unauthorized access to sensitive channel content and allow guest users to gain channel management privileges.
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Analysis
by VulDB Data Team • 07/01/2025
This vulnerability resides within the Mattermost collaboration platform and represents a critical authorization bypass flaw that undermines the platform's core permission management system. The issue affects multiple version streams including 10.5.x through 10.5.5, 9.11.x through 9.11.15, 10.8.x through 10.8.0, 10.7.x through 10.7.2, and 10.6.x through 10.6.5, indicating a widespread failure in the permission enforcement mechanism. The vulnerability specifically targets the playbook run participants feature, which is designed to manage user participation in automated workflow processes. This flaw allows authenticated users who possess only basic member-level permissions to circumvent the intended access controls that should restrict channel membership management to administrators and designated managers.
The technical implementation of this vulnerability stems from improper validation of user permissions within the playbook run functionality. When users attempt to add or remove participants from playbook runs that involve private channels, the system fails to properly verify whether the requesting user possesses the necessary 'Manage Members' permission. This represents a classic authorization bypass vulnerability that aligns with CWE-285, which addresses improper authorization within software systems. The flaw occurs at the application logic level where the permission checking mechanism is either missing or incorrectly implemented, allowing privilege escalation through an alternative attack vector that bypasses the standard access control checks.
The operational impact of this vulnerability extends beyond simple unauthorized access to include potential privilege escalation and data exposure risks. An authenticated user with basic member permissions can manipulate private channel memberships through playbook runs, effectively gaining unauthorized access to sensitive channel content that should be restricted to authorized participants only. This creates a significant risk for organizations that rely on Mattermost for confidential communications, as guest users or regular members could gain channel management capabilities that should be reserved for administrators. The vulnerability undermines the fundamental security model of Mattermost's channel-based access control system, potentially leading to data leakage, unauthorized collaboration, and compromised organizational security boundaries.
Organizations affected by this vulnerability should immediately implement mitigations including updating to patched versions of Mattermost where available, and implementing additional access controls through network-level restrictions or application firewalls. The recommended approach involves disabling the playbook run participants feature for private channels until the vulnerability is fully addressed, or implementing additional verification layers that enforce the 'Manage Members' permission even when accessing through alternative pathways. Security teams should also conduct immediate audits of channel memberships and user permissions to identify any unauthorized changes that may have occurred. This vulnerability demonstrates the importance of comprehensive permission validation across all application features and highlights the need for robust security testing that includes edge cases and alternative access paths. The ATT&CK framework would categorize this as privilege escalation through application logic flaws, specifically targeting the privilege escalation and persistence tactics that could allow attackers to maintain access to sensitive channels over time.