Headline

CVE-2023-22486: Quadratic complexity bug in handle_close_bracket may lead to a denial of service

cmark-gfm is GitHub’s fork of cmark, a CommonMark parsing and rendering library and program in C. Versions prior to 0.29.0.gfm.7 contain a polynomial time complexity issue in handle_close_bracket that may lead to unbounded resource exhaustion and subsequent denial of service. This vulnerability has been patched in 0.29.0.gfm.7.

1 year ago

CVE

Open in Source

#vulnerability #dos #git

Impact

A polynomial time complexity issue in cmark-gfm may lead to unbounded resource exhaustion and subsequent denial of service.

Proof of concept

python3 -c 'print("![[]()" * 10000)' | cmark-gfm

Increasing the number 10000 in the above command causes the running time to increase quadratically.

Patches

This vulnerability has been patched in 0.29.0.gfm.7.

Note on cmark and cmark-gfm

cmark-gfm is a fork of cmark that adds the GitHub Flavored Markdown extensions. The two codebases have diverged over time, but share a common core. This bug affects both codebases. We would like to thank @jgm for his help with fixing and disclosing this bug.

Credit

We would like to thank @jgm for implementing the fix for this bug.

References

https://en.wikipedia.org/wiki/Time_complexity

For more information

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