{"id":"CVE-2023-42821","aliases":["GHSA-m9xq-6h2j-65r2","GO-2023-2074"],"url":"https://o3.security/vulnerability/CVE-2023-42821","summary":"github.com/gomarkdown/markdown Out-of-bounds Read while parsing citations","details":"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.","published":"2023-09-22T16:55:33.355Z","modified":"2026-04-10T05:03:48.164432Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":1,"affectedPackages":[{"ecosystem":"Go","name":"github.com/gomarkdown/markdown","fixedVersion":"0.0.0-20230922105210-14b16010c2ee"}],"fix":{"url":"https://github.com/gomarkdown/markdown/commit/14b16010c2ee7ff33a940a541d993bd043a88940","label":"gomarkdown/markdown@14b1601"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/42xxx/CVE-2023-42821.json"},{"type":"WEB","url":"https://github.com/gomarkdown/markdown/blob/7478c230c7cd3e7328803d89abe591d0b61c41e4/parser/citation.go#L69"},{"type":"FIX","url":"https://github.com/gomarkdown/markdown/commit/14b16010c2ee7ff33a940a541d993bd043a88940"},{"type":"ADVISORY","url":"https://github.com/gomarkdown/markdown/security/advisories/GHSA-m9xq-6h2j-65r2"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-42821"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-04-10T05:03:48.164432Z"}}