{"resultsPerPage":1,"startIndex":0,"totalResults":1,"format":"NVD_CVE","version":"2.0","timestamp":"2026-05-04T21:28:39.187","vulnerabilities":[{"cve":{"id":"CVE-2023-26485","sourceIdentifier":"security-advisories@github.com","published":"2023-03-31T23:15:07.250","lastModified":"2024-11-21T07:51:36.963","vulnStatus":"Modified","cveTags":[],"descriptions":[{"lang":"en","value":"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.\n\n\n\n\n### Impact\n\nA polynomial time complexity issue in cmark-gfm may lead to unbounded resource exhaustion and subsequent denial of service.\n\n### Proof of concept\n\n```\n$ ~/cmark-gfm$ python3 -c 'pad = \"_\" * 100000; print(pad + \".\" + pad, end=\"\")' | time ./build/src/cmark-gfm --to plaintext\n```\n\nIncreasing the number 10000 in the above commands causes the running time to increase quadratically.\n\n### Patches\n\nThis vulnerability have been patched in 0.29.0.gfm.10.\n\n### Note on cmark and cmark-gfm\n\nXXX: TBD\n\n[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`. \n\n### Credit\n\nWe would like to thank @gravypod for reporting this vulnerability.\n\n### References\n\nhttps://en.wikipedia.org/wiki/Time_complexity\n\n### For more information\n\nIf you have any questions or comments about this advisory:\n\n* Open an issue in [github/cmark-gfm](https://github.com/github/cmark-gfm)\n"}],"metrics":{"cvssMetricV31":[{"source":"security-advisories@github.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","baseScore":5.3,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"LOW"},"exploitabilityScore":3.9,"impactScore":1.4},{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":3.6}]},"weaknesses":[{"source":"security-advisories@github.com","type":"Secondary","description":[{"lang":"en","value":"CWE-400"},{"lang":"en","value":"CWE-407"}]}],"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:github:cmark-gfm:*:*:*:*:*:*:*:*","versionEndExcluding":"0.29.0.gfm.10","matchCriteriaId":"E3CE1A70-0583-4858-9DA3-7A4E9717FE3A"}]}]}],"references":[{"url":"https://github.com/github/cmark-gfm/commit/07a66c9bc341f902878e37d7da8647d6ef150987","source":"security-advisories@github.com","tags":["Patch"]},{"url":"https://github.com/github/cmark-gfm/security/advisories/GHSA-r8vr-c48j-fcc5","source":"security-advisories@github.com","tags":["Exploit","Vendor Advisory"]},{"url":"https://github.com/github/cmark-gfm/commit/07a66c9bc341f902878e37d7da8647d6ef150987","source":"af854a3a-2127-422b-91ae-364da2661108","tags":["Patch"]},{"url":"https://github.com/github/cmark-gfm/security/advisories/GHSA-r8vr-c48j-fcc5","source":"af854a3a-2127-422b-91ae-364da2661108","tags":["Exploit","Vendor Advisory"]}]}}]}