PT-2026-28423 · Mattermost · Mattermost

Winfunc · Published 2026-03-26 · Updated 2026-03-26 · CVE-2026-3114

Positive Technologies (AI Summary)

CVSS v3.1

6.5

Medium

Base vector

AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Name of the Vulnerable Software and Affected Versions Mattermost versions 10.11.x through 10.11.11 Mattermost versions 11.2.x through 11.2.3 Mattermost versions 11.3.x through 11.3.1 Mattermost versions 11.4.x through 11.4.0

Description The software does not properly validate the size of decompressed archive entries when extracting files. This allows authenticated users who have file upload permissions to cause a denial of service by uploading specially crafted zip archives. These archives contain highly compressed entries, known as zip bombs, which can exhaust server memory.

Recommendations Update Mattermost to a version later than 10.11.11. Update Mattermost to a version later than 11.2.3. Update Mattermost to a version later than 11.3.1. Update Mattermost to a version later than 11.4.0.

Fix

Weakness Enumeration

CWE-409

Related Identifiers

CVE-2026-3114

GHSA-VHGH-G7X8-4RX8

Affected Products

Mattermost

References · 4

• https://osv.dev/vulnerability/GHSA-vhgh-g7x8-4rx8 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-3114 · Security Note
• https://mattermost.com/security-updates · Vendor Advisory
• https://github.com/mattermost/mattermost · Note