{"cve":"CVE-2021-39199","nvd":{"published":"2021-09-07T19:15:08.747","modified":"2026-06-17T04:03:17.840","status":"Modified","description":"remark-html is an open source nodejs library which compiles Markdown to HTML. In affected versions the documentation of remark-html has mentioned that it was safe by default. In practice the default was never safe and had to be opted into. That is, user input was not sanitized. This means arbitrary HTML can be passed through leading to potential XSS attacks. The problem has been patched in 13.0.2 and 14.0.1: `remark-html` is now safe by default, and the implementation matches the documentation. On older affected versions, pass `sanitize: true` if you cannot update.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1},"cwes":["CWE-79"],"references":["https://github.com/remarkjs/remark-html/commit/b75c9dde582ad87ba498e369c033dc8a350478c1","https://github.com/remarkjs/remark-html/releases/tag/14.0.1","https://github.com/remarkjs/remark-html/security/advisories/GHSA-9q5w-79cv-947m","https://www.npmjs.com/package/remark-html","https://github.com/remarkjs/remark-html/commit/b75c9dde582ad87ba498e369c033dc8a350478c1"],"products":["remark:remark-html"],"source":"nvd","synced_at":"2026-10-19T21:21:57.125947417+00:00"},"epss":{"cve":"CVE-2021-39199","score":0.01075,"percentile":0.64974,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-9q5w-79cv-947m","url":"https://osv.dev/vulnerability/GHSA-9q5w-79cv-947m","summary":"Unsafe defaults in `remark-html`","modified":"2026-07-08T06:28:59.698476878Z","packages":[{"ecosystem":"npm","name":"remark-html","purl":"pkg:npm/remark-html","ranges":["<13.0.2"],"fixed":["13.0.2"]},{"ecosystem":"npm","name":"remark-html","purl":"pkg:npm/remark-html","ranges":[">=14.0.0 <14.0.1"],"fixed":["14.0.1"]}]}],"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."]}