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Fencer Vulns
medium 5.3

CVE-2023-22485 json

cmark-gfm out-of-bounds read in validate_protocol

published 2023-01-24 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-26632

cvss
5.3
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 54%
public exploits
0
none known

Summary

cmark-gfm is GitHub's fork of cmark, a CommonMark parsing and rendering library and program in C. In versions prior 0.29.0.gfm.7, a crafted markdown document can trigger an out-of-bounds read in the `validate_protocol` function. We believe this bug is harmless in practice, because the out-of-bounds read accesses `malloc` metadata without causing any visible damage.This vulnerability has been patched in 0.29.0.gfm.7.

Patch / fix

  • github cmark-gfm 0.29.0.gfm.7
  • 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 1.9.0-1
  • ruby-commonmarker Debian 14, Debian 13 0.23.10-1

debian advisories DEBIAN-CVE-2023-22485

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-22485 updated

cmark-gfm: multiple vulnerabilities

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
19 mo ago

Exploit prediction

0.73% chance of exploitation in the next 30 days, higher than 54% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/github/cmark-gfm/security/advisories/GHSA-c944-cv5f-hpvr referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Affected products

  • github cmark-gfm

Classification

Weakness

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.