High severity7.5NVD Advisory· Published Sep 7, 2026

CVE-2026-86435

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.

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

Affected products

Thephpleague/Commonmarkllm-fuzzy
Range: from 1.5.0 before 2.8.4

Patches

Vulnerability mechanics

References

github.com/thephpleague/commonmark/security/advisories/GHSA-jfm3-95jq-q3rfnvd
www.vulncheck.com/advisories/commonmark-1.5.0-before-2.8.4-denial-of-service-via-footnotenvd

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