CVE-2026-6340

MediumCVSS 6.5/10Last modified Oct 14, 2026

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

Metrics

CVSS 3.1 6.5/10CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness enumeration

CWE-789

Affected software

Vendor	Product	Versions
Mattermost	Mattermost	>= 11.5.0, <= 11.5.1; >= 10.11.0, <= 10.11.13; >= 11.4.0, <= 11.4.3

References

https://mattermost.com/security-updatesVendor Advisory

Timeline

Published: May 18, 2026
Last modified: Oct 14, 2026
NVD status: Analyzed

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