commonmark versions from 1.5.0 before 2.8.4 contain a denial of service vulnerability in the Footnote extension that fails to deduplicate footnote definitions. Attackers can craft documents with duplicate footnote definitions and references to create quadratic output expansion, consuming excessive memory and CPU to exhaust server resources.
History

Thu, 10 Sep 2026 10:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Mon, 07 Sep 2026 13:00:00 +0000

Type Values Removed Values Added
Description commonmark versions from 1.5.0 before 2.8.4 contain a denial of service vulnerability in the Footnote extension that fails to deduplicate footnote definitions. Attackers can craft documents with duplicate footnote definitions and references to create quadratic output expansion, consuming excessive memory and CPU to exhaust server resources.
Title commonmark 1.5.0 before 2.8.4 Denial of Service via Footnote
First Time appeared Thephpleague
Thephpleague commonmark
Weaknesses CWE-407
CPEs cpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:*
Vendors & Products Thephpleague
Thephpleague commonmark
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published: 2026-09-07T12:53:53.897Z

Updated: 2026-09-09T14:32:07.292Z

Reserved: 2026-09-07T12:34:31.457Z

Link: CVE-2026-86435

cve-icon Vulnrichment

Updated: 2026-09-09T14:31:57.195Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-09-07T13:20:43.013

Modified: 2026-09-09T15:17:18.217

Link: CVE-2026-86435

cve-icon Redhat

No data.