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VULNERABILITIES

CVE-2026-86428 Details

Description

commonmark versions from 1.5.0 before 2.10.0 contain a denial of service vulnerability in the AttributesExtension when processing distinctly-named attributes. Attackers can submit Markdown with numerous distinct attribute names to cause quadratic-time attribute merging and filtering, consuming disproportionate CPU resources and preventing legitimate requests from completing.

Metrics

CVSS 3.x Severity and Vector Strings:

CNA: [email protected]CVSS-B:7.5 HIGHVector:CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References to Advisories, Solutions, and Tools

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URLSource(s)Tag(s)
https://github.com/thephpleague/commonmark/security/advisories/GHSA-8rr7-cvq3-gmfh [email protected]MitigationVendor Advisory
https://www.vulncheck.com/advisories/commonmark-1.5.0-before-2.10.0-denial-of-service-via-attributes [email protected]Third Party Advisory

Weakness Enumeration

CWE-IDCWE NameSource
CWE-407Inefficient Algorithmic Complexity[email protected]

Affected Products

ProductVersions
thephpleague commonmark
>= 1.5.0, < 2.10.0

CPE

  • cpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:*

Remediation

  • No remediation found in references.

Change History

3 change records found show changes

QUICK INFO

CVE Dictionary Entry:
CVE-2026-86428
NVD Published Date:
Sep 7, 2026
NVD Last Modified:
Sep 9, 2026
Source:
[email protected]
CVE-2026-86428 Details - Not Deferred