CVE-2024-1952: 
vulnerability analysis and mitigation

Mattermost version 8.1.x before 8.1.9 contains a vulnerability in the data sanitization process associated with permalinks when a plugin updates an ephemeral post. This security flaw was assigned CVE-2024-1952 and was disclosed on February 29, 2024. The vulnerability affects Mattermost Server versions from 8.1.0 up to (excluding) 8.1.9 (NVD).

The vulnerability stems from a failure to properly sanitize data associated with permalinks during plugin-based ephemeral post updates. The severity of this vulnerability has been assessed with two different CVSS v3.1 scores: NIST rates it as MEDIUM with a base score of 4.3 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N), while Mattermost, Inc. rates it as LOW with a base score of 3.1 (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N). The vulnerability is classified under CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor) (NVD).

When exploited, this vulnerability allows an authenticated attacker who can control the ephemeral post update to access individual posts' contents in channels they are not a member of, potentially leading to unauthorized access to sensitive information (NVD).

The recommended mitigation is to upgrade to Mattermost version 8.1.9 or later, which contains the fix for this vulnerability (Vendor Advisory).