Resource exhaustion in GitHub Cmark-Gfm

CVE-2022-39209

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.

Vulnerability class: DoS (Denial of Service)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.021 (81.3th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 81st percentile — 81.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2022-39209: held from 0.017 to 0.021.

EPSS over last 30 days · oldest: 0.017 · newest: 0.021 · change: +0.004

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2022-39209?
CVE-2022-39209 is a high-severity vulnerability in GitHub Cmark-Gfm, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2022-09-15.
How severe is CVE-2022-39209?
High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2022-39209 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.