Description
Mattermost versions 11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11 fail to validate decompressed archive entry sizes during file extraction which allows authenticated users with file upload permissions to cause a denial of service via crafted zip archives containing highly compressed entries (zip bombs) that exhaust server memory.. Mattermost Advisory ID: MMSA-2026-00598
Problem types
CWE-409: Improper Handling of Highly Compressed Data (Data Amplification)
Product status
11.4.0 (semver)
11.3.0 (semver)
11.2.0 (semver)
10.11.0 (semver)
11.5.0
11.4.1
11.3.2
11.2.4
10.11.12
Credits
winfunc
References
mattermost.com/security-updates (MMSA-2026-00598)