CVE-2026-86433

commonmark versions from 1.5.0 before 2.8.4 contain a denial of service vulnerability in the Attributes extension where AttributesListener::findTargetAndDirection() performs quadratic-time sibling list scanning. Unauthenticated attackers can submit approximately 32 KB of repeated attribute blocks to cause parsing to take over 5 seconds, exhausting server resources.

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-g2gp-3wwq-f4ph
https://www.vulncheck.com/advisories/commonmark-1.5.0-before-2.8.4-denial-of-service-via-attributes

Configurations

No configuration.

History

No history.

Information

Published : 2026-09-07 13:20

Updated : 2026-09-08 19:57

NVD link : CVE-2026-86433

Mitre link : CVE-2026-86433

CVE.ORG link : CVE-2026-86433

JSON object : View

Products Affected

No product.

CWE

CWE-407

Inefficient Algorithmic Complexity

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