CVE-2022-39209: Fedoraproject Fedora

Medium severity, CVSS 6.5. EPSS: 2.2% chance of exploitation in the next 30 days.

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.

Affected products

• Fedoraproject Fedora: version 35 only; version 36 only; version 37 only
• GitHub Cmark-Gfm: before 0.29.0.gfm.6 (fixed in 0.29.0.gfm.6)

Published 2022-09-15. Last modified 2026-06-17.