GitHub Advisoryadvisory · Go

GHSA-cjm8-jxpw-g43m Mattermost doesn't validate 7zip archive structure before processing

MEDIUM Published 2026-05-18 Modified 2026-06-01 Official page ↗
Aliases
CVE-2026-6340
Ecosystem
Go
Packages
github.com/mattermost/mattermost/server/v8, github.com/mattermost/mattermost-server
Severity
Moderate
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Weaknesses
CWE-789
Reviewed
2026-06-01

Affected packages

• Go github.com/mattermost/mattermost/server/v8: >= 11.5.0, < 11.5.2 → fixed in 11.5.2 • Go github.com/mattermost/mattermost/server/v8: >= 10.11.0, < 10.11.14 → fixed in 10.11.14 • Go github.com/mattermost/mattermost/server/v8: >= 11.4.0, < 11.4.4 → fixed in 11.4.4 • Go github.com/mattermost/mattermost/server/v8: < 8.0.0-20260325191733-fb11968f8798 → fixed in 8.0.0-20260325191733-fb11968f8798 • Go github.com/mattermost/mattermost-server: < 5.3.2-0.20260325191733-fb11968f8798 → fixed in 5.3.2-0.20260325191733-fb11968f8798

Description

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to validate 7zip archive structure before processing which allows an authenticated attacker to cause server memory exhaustion and denial of service via uploading a specially crafted 7zip file with excessive folder declarations.. Mattermost Advisory ID: MMSA-2026-00573

Related

Alias · CVE (1)

  • CVE-2026-6340 Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to validate 7zip archive structure before processing which… vulnerability

Weakness · CWE (1)

  • CWE-789 Memory Allocation with Excessive Size Value weakness

References