8.8

CVE-2026-3524: mattermost legal_hold Missing Authorization

CVSS: 8.8v3.1HighAnalyzed
Published 06-04-2026Last modified 07-04-2026
Open JSON

Vulnerability summary

CVE-2026-3524 is a high (CVSS 8.8) Missing Authorization vulnerability in mattermost legal_hold. EPSS estimates a 0.42% chance of exploitation in the next 30 days, higher than 34.9% of scored vulnerabilities.

Overall risk
35/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.8/10
010
High · v3.1 (NVD)
EPSS score
0.42%
0%100%
Low · +0.04 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 06-04-2026
    PublishedVulnerability first disclosed.
  2. 07-04-2026
    Last modifiedVulnerability information updated.

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

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.42%

Chance of exploitation in the next 30 days

Percentile

35%

Versus all other CVEs

30-day change

+0.04 pp

From 0.38% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.42%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Mattermost2 products

1 vendor · 2 products

References

1 links