{"id":"GHSA-4r62-v4vq-hr96","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)","aliases":["CVE-2021-21306"],"modified":"2026-09-10T03:49:13.926993251Z","published":"2021-02-08T21:17:58Z","database_specific":{"severity":"MODERATE","github_reviewed":true,"github_reviewed_at":"2021-02-08T21:17:26Z","nvd_published_at":"2021-02-08T22:15:00Z","cwe_ids":["CWE-400"]},"references":[{"type":"WEB","url":"https://github.com/markedjs/marked/security/advisories/GHSA-4r62-v4vq-hr96"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-21306"},{"type":"WEB","url":"https://github.com/markedjs/marked/issues/1927"},{"type":"WEB","url":"https://github.com/markedjs/marked/pull/1864"},{"type":"WEB","url":"https://github.com/markedjs/marked/commit/7293251c438e3ee968970f7609f1a27f9007bccd"},{"type":"WEB","url":"https://www.npmjs.com/package/marked"}],"affected":[{"package":{"name":"marked","ecosystem":"npm","purl":"pkg:npm/marked"},"ranges":[{"type":"SEMVER","events":[{"introduced":"1.1.1"},{"fixed":"2.0.0"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2021/02/GHSA-4r62-v4vq-hr96/GHSA-4r62-v4vq-hr96.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"}]}