Impact CommonMarker uses "cmark-gfm" for rendering "Github Flavored Markdown" (https://github.github.com/gfm/). A polynomial time complexity issue in cmark-gfm's autolink extension may lead to unbounded resource exhaustion and subsequent denial of service. Patches This vulnerability has been patched in the following CommonMarker release: - v0.23.6 Workarounds Disable use of the autolink extension. References https://github.com/gjtorikian/commonmarker/pull/190 https://github.com/github/cmark-gfm/security/advisories/GHSA-cgh3-p57x-9q7q https://en.wikipedia.org/wiki/Time_complexity For more information If you have any questions or comments about this advisory: * Open an issue in "github/cmark-gfm" (https://github.com/github/cmark-gfm) Acknowledgements We would like to thank "Legit Security" (https://www.legitsecurity.com) for reporting this vulnerability.