CVE-2026-3114
Mattermost doesn't validate decompressed archive entry sizes during file extraction
6.5
MEDIUM
CVSS 3.1
EPSS 0.02%
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.
How to fix CVE-2026-3114
To remediate CVE-2026-3114, upgrade the affected package to a fixed version below.
- —upgrade to 11.4.1 or later
Is CVE-2026-3114 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- >= 11.4.0, < 11.4.1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |