CVE-2026-86435

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.

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-jfm3-95jq-q3rf
https://www.vulncheck.com/advisories/commonmark-1.5.0-before-2.8.4-denial-of-service-via-footnote

Configurations

No configuration.

History

No history.

Information

Published : 2026-09-07 13:20

Updated : 2026-09-09 15:17

NVD link : CVE-2026-86435

Mitre link : CVE-2026-86435

CVE.ORG link : CVE-2026-86435

JSON object : View

Products Affected

No product.

CWE

CWE-407

Inefficient Algorithmic Complexity

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