CVE-2026-86349

MediumCVSS 4.3/10Last modified Oct 7, 2026

Description

Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.8, 10.11.x <= 10.11.22 fail to limit the nesting depth in the server-side Markdown parser which allows an authenticated attacker to cause a denial of service (CPU resource exhaustion) via a crafted post containing deeply nested blockquotes or list items.. Mattermost Advisory ID: MMSA-2026-00707

Metrics

CVSS 3.1 4.3/10CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

Weakness enumeration

CWE-407

Affected software

Vendor	Product	Versions
Mattermost	Mattermost	>= 11.9.0, <= 11.9.0; >= 11.8.0, <= 11.8.4; >= 11.7.0, <= 11.7.8; >= 10.11.0, <= 10.11.22

References

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

Timeline

Published: Sep 14, 2026
Last modified: Oct 7, 2026
NVD status: Analyzed

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