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TI-2023-08734 Aliases CVE-2023-22485

cmark-gfm out-of-bounds read in validate_protocol

Priority MEDIUM 63CWE-125Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Information disclosure
Confidentiality · integrity · availability
Low · None · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-125 and the CVSS impact.

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.0073 54th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed cmark-gfm (github): 0.29.0.gfm.7

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
GitHubcmark-gfmbefore 0.29.0.gfm.70.29.0.gfm.7Patch availableCNA
  • cmark-gfm VendorGitHub Affected before 0.29.0.gfm.7 Fixed in 0.29.0.gfm.7 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:github:cmark-gfm:*:*:*:*:*:*:*:*before 0.29.0.gfm.7VulnerableGitHub
  • cpe:2.3:a:github:cmark-gfm:*:*:*:*:*:*:*:* Versions before 0.29.0.gfm.7 Vulnerable ·GitHub

Remediation

  • Fix · CNA cmark-gfm (github) Fixed in 0.29.0.gfm.7

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2023-22485

References

Exploit 1

  • TI-2022-08539 Integer overflow in table parsing extension leads to heap memory corruption CVSS 3.1CRITICAL 9.8
  • TI-2023-11632 Quadratic complexity may lead to a denial of service in cmark-gfm CVSS 3.1HIGH 7.5
  • TI-2023-10324 Quadratic complexity may lead to a denial of service in cmark-gfm CVSS 3.1HIGH 7.5
  • TI-2023-19072 Quadratic complexity bugs may lead to a denial of service CVSS 3.1HIGH 7.5
  • TI-2023-08735 cmark-gfm Quadratic complexity bug in handle_close_bracket may lead to a denial of service CVSS 3.1HIGH 7.5
  • TI-2023-08733 Inefficient Quadratic complexity bug in handle_pointy_brace may lead to a denial of service CVSS 3.1HIGH 7.5
See all 9 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences