Vulnerability · Published Apr 6, 2026 · Assigned by Mattermost
CVE-2026-3524Authorization Bypass in Mattermost Legal Hold Plugin Due to Missing Return After Permission Check
High 8.3
In plain English
A high-severity missing authorization in Mattermost from Mattermost. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 33% of all known vulnerabilities).
Severity (CVSS 3.1)8.3High
Exploit odds (30 days)0.4%top 67.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
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
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mattermost | Mattermost | 0 – through 1.1.4 |
Weakness: CWE-862 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
References
- MMSA-2026-00621 vendor-advisory