http://bugzilla.opensuse.org/show_bug.cgi?id=1210041 Bug ID: 1210041 Summary: VUL-0: CVE-2023-26485: ghc-cmark-gfm: polynomial time complexity during rendering leads to DoS Classification: openSUSE Product: openSUSE Distribution Version: Leap 15.4 Hardware: Other OS: Other Status: NEW Severity: Normal Priority: P5 - None Component: Security Assignee: dmueller@suse.com Reporter: carlos.lopez@suse.com QA Contact: security-team@suse.de CC: peter.simons@suse.com Found By: --- Blocker: --- CVE-2023-26485 cmark-gfm is GitHub's fork of cmark, a CommonMark parsing and rendering library and program in C. A polynomial time complexity issue in cmark-gfm may lead to unbounded resource exhaustion and subsequent denial of service. This CVE covers quadratic complexity issues when parsing text which leads with either large numbers of `_` characters. This issue has been addressed in version 0.29.0.gfm.10. Users are advised to upgrade. Users unable to upgrade should validate that their input comes from trusted sources. ### Impact A polynomial time complexity issue in cmark-gfm may lead to unbounded resource exhaustion and subsequent denial of service. ### Proof of concept ``` $ ~/cmark-gfm$ python3 -c 'pad = "_" * 100000; print(pad + "." + pad, end="")' | time ./build/src/cmark-gfm --to plaintext ``` Increasing the number 10000 in the above commands causes the running time to increase quadratically. ### Patches This vulnerability have been patched in 0.29.0.gfm.10. ### Note on cmark and cmark-gfm XXX: TBD [cmark-gfm](https://github.com/github/cmark-gfm) is a fork of [cmark](https://github.com/commonmark/cmark) that adds the GitHub Flavored Markdown extensions. The two codebases have diverged over time, but share a common core. These bugs affect both `cmark` and `cmark-gfm`. ### Credit We would like to thank @gravypod for reporting this vulnerability. ### References 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) References: http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2023-26485 https://www.cve.org/CVERecord?id=CVE-2023-26485 http://www.cvedetails.com/cve/CVE-2023-26485/ https://github.com/github/cmark-gfm/commit/07a66c9bc341f902878e37d7da8647d6e... https://github.com/github/cmark-gfm/security/advisories/GHSA-r8vr-c48j-fcc5 -- You are receiving this mail because: You are on the CC list for the bug.