{"cve":"CVE-2023-42821","nvd":{"published":"2023-09-22T17:15:14.990","modified":"2026-06-17T06:24:35.577","status":"Modified","description":"The package `github.com/gomarkdown/markdown` is a Go library for parsing Markdown text and rendering as HTML. Prior to pseudoversion `0.0.0-20230922105210-14b16010c2ee`, which corresponds with commit `14b16010c2ee7ff33a940a541d993bd043a88940`, parsing malformed markdown input with parser that uses parser.Mmark extension could result in out-of-bounds read vulnerability. To exploit the vulnerability, parser needs to have `parser.Mmark` extension set. The panic occurs inside the `citation.go` file on the line 69 when the parser tries to access the element past its length. This can result in a denial of service. Commit `14b16010c2ee7ff33a940a541d993bd043a88940`/pseudoversion `0.0.0-20230922105210-14b16010c2ee` contains a patch for this issue.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-125"],"references":["https://github.com/gomarkdown/markdown/blob/7478c230c7cd3e7328803d89abe591d0b61c41e4/parser/citation.go#L69","https://github.com/gomarkdown/markdown/commit/14b16010c2ee7ff33a940a541d993bd043a88940","https://github.com/gomarkdown/markdown/security/advisories/GHSA-m9xq-6h2j-65r2","https://github.com/gomarkdown/markdown/blob/7478c230c7cd3e7328803d89abe591d0b61c41e4/parser/citation.go#L69","https://github.com/gomarkdown/markdown/commit/14b16010c2ee7ff33a940a541d993bd043a88940"],"products":["gomarkdown:markdown"],"source":"nvd","synced_at":"2026-10-19T21:39:34.467980132+00:00"},"epss":{"cve":"CVE-2023-42821","score":0.01252,"percentile":0.69451,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-m9xq-6h2j-65r2","url":"https://osv.dev/vulnerability/GHSA-m9xq-6h2j-65r2","summary":"Markdown vulnerable to Out-of-bounds Read while parsing citations","modified":"2026-09-10T03:49:58.454932808Z","packages":[{"ecosystem":"Go","name":"github.com/gomarkdown/markdown","purl":"pkg:golang/github.com/gomarkdown/markdown","ranges":["<0.0.0-20230922105210-14b16010c2ee"],"fixed":["0.0.0-20230922105210-14b16010c2ee"]}]},{"id":"GO-2023-2074","url":"https://osv.dev/vulnerability/GO-2023-2074","summary":"Parser out-of-bounds read caused by a malformed markdown input in github.com/gomarkdown/markdown","modified":"2024-05-20T16:03:47Z","packages":[{"ecosystem":"Go","name":"github.com/gomarkdown/markdown","purl":"pkg:golang/github.com/gomarkdown/markdown","ranges":["<0.0.0-20230922105210-14b16010c2ee"],"fixed":["0.0.0-20230922105210-14b16010c2ee"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}