CVE-2024-32045 in Mattermost
Summary
by MITRE • 05/26/2024
Mattermost versions 9.5.x <= 9.5.3, 9.6.x <= 9.6.1, 8.1.x <= 8.1.12 fail to enforce proper access controls for channel and team membership when linking a playbook run to a channel which allows members to link their runs to private channels they were not members of.
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Analysis
by VulDB Data Team • 09/30/2025
The vulnerability described in CVE-2024-32045 represents a critical access control flaw within Mattermost's playbook integration functionality. This issue affects multiple version branches including 9.5.x through 9.5.3, 9.6.x through 9.6.1, and 8.1.x through 8.1.12, indicating a widespread problem that has persisted across several major releases. The flaw specifically targets the authorization mechanisms that govern channel and team membership when establishing connections between playbook runs and channels, creating a significant security gap in the platform's permission model.
The technical implementation of this vulnerability stems from insufficient validation of user permissions during the playbook run-channel linking process. When users attempt to associate a playbook run with a channel, the system fails to properly verify whether the requesting user has adequate membership privileges for the target channel. This oversight allows unauthorized users to establish connections between their playbook runs and private channels where they lack proper membership rights, effectively bypassing the intended access controls that should prevent such associations.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass potential data exposure and privilege escalation risks. An attacker with access to the Mattermost platform could exploit this flaw to gain visibility into private channel content through playbook run associations, potentially accessing sensitive information that should only be available to legitimate channel members. This weakness undermines the fundamental security model of private channels and team-based access controls that Mattermost relies upon to maintain information segregation and confidentiality.
This vulnerability aligns with CWE-285, which addresses improper authorization in software systems, and demonstrates characteristics consistent with ATT&CK technique T1078.004 for valid accounts and T1566 for credential theft, as it enables unauthorized access through legitimate user accounts. The flaw particularly impacts the platform's integrity and confidentiality controls, as it allows users to circumvent established membership restrictions that are critical for maintaining secure communication boundaries within organizations.
Organizations utilizing affected Mattermost versions should immediately implement mitigations including immediate patching to the latest available releases, implementing additional access monitoring for playbook run-channel associations, and conducting thorough audits of existing playbook run-channel linkages to identify and remove unauthorized associations. Security teams should also consider implementing network-level restrictions and additional logging mechanisms to detect anomalous access patterns that might indicate exploitation attempts. The vulnerability highlights the critical importance of proper access control validation in integrated collaboration platforms where multiple security domains intersect through automated workflow integrations.