CVE-2026-3524 PUBLISHED

Authorization Bypass in Mattermost Legal Hold Plugin Due to Missing Return After Permission Check

Assigner: Mattermost
Reserved: 04.03.2026 Published: 06.04.2026 Updated: 06.04.2026

Mattermost Plugin Legal Hold versions <=1.1.4 fail to halt request processing after a failed authorization check in ServeHTTP which allows an authenticated attacker to access, create, download, and delete legal hold data via crafted API requests to the plugin's endpoints. Mattermost Advisory ID: MMSA-2026-00621

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS Score: 8.3

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	High
Privileges Required	Low	Integrity Impact	High
User Interaction	None	Availability Impact	High

CVSS 3.1

Product Status

Vendor	Mattermost
Product	Mattermost
Versions	Default: unaffected affected from 0 to 1.1.4 (incl.) Version 1.1.5 is unaffected

Solutions

Update Mattermost Plugins to versions 1.1.5 or higher.

Credits

Hassan Mohammed finder

References

MMSA-2026-00621

Problem Types

CWE-862: Missing Authorization CWE