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.