TI-2022-18588 Aliases CVE-2022-39209

Uncontrolled Resource Consumption in cmark-gfm

MEDIUM 43CWE-400Published 2022-09-15 · Updated 2025-04-23

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-400.

Summary

cmark-gfm is GitHub's fork of cmark, a CommonMark parsing and rendering library and program in C. In versions prior to 0.29.0.gfm.6 a polynomial time complexity issue in cmark-gfm's autolink extension may lead to unbounded resource exhaustion and subsequent denial of service. Users may verify the patch by running `python3 -c 'print("![l"* 100000 + "\n")' | ./cmark-gfm -e autolink`, which will resource exhaust on unpatched cmark-gfm but render correctly on patched cmark-gfm. This vulnerability has been patched in 0.29.0.gfm.6. Users are advised to upgrade. Users unable to upgrade should disable the use of the autolink extension.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.02151 82nd percentileScored 2026-11-07

Fix Fixed cmark-gfm (github): 0.29.0.gfm.6

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
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

Vendor	Product	Affected versions	Fixed in	Status	Source
GitHub	cmark-gfm	before 0.29.0.gfm.6	0.29.0.gfm.6	Patch available	CNA

cmark-gfm VendorGitHub Affected before 0.29.0.gfm.6 Fixed in 0.29.0.gfm.6 Patch available CNA

CPE configurations NVD · 4

CPE	Versions	Role	Vendor
cpe:2.3:a:github:cmark-gfm::::::::	before 0.29.0.gfm.6	Vulnerable	GitHub
cpe:2.3:o:fedoraproject:fedora:35:::::::*	35	Vulnerable	Fedoraproject
cpe:2.3:o:fedoraproject:fedora:36:::::::*	36	Vulnerable	Fedoraproject
cpe:2.3:o:fedoraproject:fedora:37:::::::*	37	Vulnerable	Fedoraproject

cpe:2.3:a:github:cmark-gfm:*:*:*:*:*:*:*:* Versions before 0.29.0.gfm.6 Vulnerable ·GitHub
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:* Versions 35 Vulnerable ·Fedoraproject
cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:* Versions 36 Vulnerable ·Fedoraproject
cpe:2.3:o:fedoraproject:fedora:37:*:*:*:*:*:*:* Versions 37 Vulnerable ·Fedoraproject

Remediation

Fix · CNA cmark-gfm (github) Fixed in 0.29.0.gfm.6

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Not affected: 1 product

Red Hat 3scale API Management Platform 2

Timeline

2026-10-02 Threatist record created from CVE-2022-39209

References

Patch 1

https://github.com/github/cmark-gfm/commit/9d57d8a23142b316282bdfc954cb0ecda40a8655

Advisory 5

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