{"id":"CVE-2021-21306","aliases":["GHSA-4r62-v4vq-hr96"],"url":"https://o3.security/vulnerability/CVE-2021-21306","summary":"Regular Expression Denial of Service (REDoS) in Marked","details":"### Impact\n_What kind of vulnerability is it? Who is impacted?_\n\n[Regular expression Denial of Service](https://owasp.org/www-community/attacks/Regular_expression_Denial_of_Service_-_ReDoS)\n\nA Denial of Service attack can affect anyone who runs user generated code through `marked`.\n\n### Patches\n_Has the problem been patched? What versions should users upgrade to?_\n\npatched in v2.0.0\n\n### Workarounds\n_Is there a way for users to fix or remediate the vulnerability without upgrading?_\n\nNone.\n\n### References\n_Are there any links users can visit to find out more?_\n\nhttps://github.com/markedjs/marked/issues/1927\nhttps://owasp.org/www-community/attacks/Regular_expression_Denial_of_Service_-_ReDoS\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [marked](https://github.com/markedjs/marked/issues)","published":"2021-02-08T22:15:12.450Z","modified":"2026-07-09T01:26:06.897278Z","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":0,"affectedPackages":[{"ecosystem":"npm","name":"marked","fixedVersion":"2.0.0"}],"fix":{"url":"https://github.com/markedjs/marked/commit/7293251c438e3ee968970f7609f1a27f9007bccd","label":"markedjs/marked@7293251"},"references":[{"type":"ADVISORY","url":"https://github.com/markedjs/marked/issues/1927"},{"type":"ADVISORY","url":"https://github.com/markedjs/marked/security/advisories/GHSA-4r62-v4vq-hr96"},{"type":"ADVISORY","url":"https://www.npmjs.com/package/marked"},{"type":"FIX","url":"https://github.com/markedjs/marked/commit/7293251c438e3ee968970f7609f1a27f9007bccd"},{"type":"FIX","url":"https://github.com/markedjs/marked/pull/1864"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-21306"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-09T01:26:06.897278Z"}}