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Fencer Vulns
medium 6.4

CVE-2023-37463 json

Quadratic complexity bugs may lead to a denial of service

published 2023-07-13 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-41361

cvss
6.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 53%
public exploits
0
none known

Summary

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.

Patch / fix

  • github cmark-gfm 0.29.0.gfm.12
  • cmark-gfm Debian 14, Debian 13 0.29.0.gfm.13-1
  • python-cmarkgfm Debian 14, Debian 13 2024.11.20-1
  • r-cran-commonmark Debian 14, Debian 13 1.9.1-1
  • ruby-commonmarker Debian 14, Debian 13 0.23.10-1

debian advisories DEBIAN-CVE-2023-37463

  • python-cmarkgfm openSUSE Tumbleweed 2025.10.22-1.4

opensuse advisories openSUSE-SU-2026:12003-1

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.70% chance of exploitation in the next 30 days, higher than 53% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/github/cmark-gfm/security/advisories/GHSA-w4qg-3vf7-m9x5 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.4 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • github cmark-gfm

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.