What’s Vulnerable › Vulnerabilities

CVE-2023-24824: Quadratic complexity may lead to a denial of service in cmark-gfm

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.0% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2023-03-31 · updated 2026-06-17
• Weakness: CWE-400

Description

cmark-gfm is GitHub's fork of cmark, a CommonMark parsing and rendering library and program in C. A polynomial time complexity issue in cmark-gfm may lead to unbounded resource exhaustion and subsequent denial of service. This CVE covers quadratic complexity issues when parsing text which leads with either large numbers of `>` or `-` characters. This issue has been addressed in version 0.29.0.gfm.10. Users are advised to upgrade. Users unable to upgrade should validate that their input comes from trusted sources.

Affected products

• github cmark-gfm: before 0.29.0.gfm.10. — fixed in 0.29.0.gfm.10.

How to fix

Upgrade to a fixed version: github cmark-gfm 0.29.0.gfm.10.. Check the vendor advisory for mitigations.

References

• https://github.com/github/cmark-gfm/commit/2300c1bd2c8226108885bf019655c4159cf26b59
• https://github.com/github/cmark-gfm/security/advisories/GHSA-66g8-4hjf-77xh
• https://github.com/github/cmark-gfm/commit/2300c1bd2c8226108885bf019655c4159cf26b59
• https://github.com/github/cmark-gfm/security/advisories/GHSA-66g8-4hjf-77xh

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