CVE-2026-86428

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.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/thephpleague/commonmark/security/advisories/GHSA-8rr7-cvq3-gmfh	Mitigation Vendor Advisory
https://www.vulncheck.com/advisories/commonmark-1.5.0-before-2.10.0-denial-of-service-via-attributes	Third Party Advisory

Configurations

Configuration 1 (hide)

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

History

No history.

Information

Published : 2026-09-07 13:20

Updated : 2026-09-09 16:31

NVD link : CVE-2026-86428

Mitre link : CVE-2026-86428

CVE.ORG link : CVE-2026-86428

JSON object : View

Products Affected

thephpleague

commonmark

CWE

CWE-407

Inefficient Algorithmic Complexity

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