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)
EPSS: 0.017 (74.9th percentile) — read the EPSS interpretation.
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.
Affected products
- Github Cmark-gfm — versions < 0.29.0.gfm.6
- Fedoraproject Fedora — versions 35, 36, 37
Weakness classification (CWE)
Public proof-of-concept exploits
References
- security-advisories@github.com (Third Party Advisory)
- security-advisories@github.com (Patch, Third Party Advisory)
- security-advisories@github.com (Third Party Advisory)
- security-advisories@github.com (vendor-advisory)
- security-advisories@github.com (vendor-advisory)
- security-advisories@github.com (vendor-advisory)
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.