CVE-2023-37463 — cmark-gfm is an extended version of the C reference implementation of CommonMark

cmark-gfm is an extended version of the C reference implementation of CommonMark, a rationalized version of Markdown syntax with a spec. Three polynomial time complexity issues in cmark-gfm may lead to unbounded resource exhaustion and subsequent denial of service. These vulnerab

01What is this vulnerability?

cmark-gfm is an extended version of the C reference implementation of CommonMark, a rationalized version of Markdown syntax with a spec. Three polynomial time complexity issues in cmark-gfm may lead to unbounded resource exhaustion and subsequent denial of service. These vulnerabilities have been patched in 0.29.0.gfm.12.

02Affected products

Vendor	Product	Versions
github	cmark	gfm — < 0.29.0.gfm.12

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2023-07-13T19:22:16.654Z
• Last modified: 2024-10-30T18:48:32.341Z

09References

• github.com — https://github.com/github/cmark-gfm/security/advisories/GHSA-w4qg-3vf7-m9x5
• github.com — https://github.com/github/cmark-gfm/releases/tag/0.29.0.gfm.12