{"cve":"CVE-2020-26870","nvd":{"published":"2020-10-07T16:15:18.030","modified":"2026-06-17T03:08:26.847","status":"Modified","description":"Cure53 DOMPurify before 2.0.17 allows mutation XSS. This occurs because a serialize-parse roundtrip does not necessarily return the original DOM tree, and a namespace can change from HTML to MathML, as demonstrated by nesting of FORM elements.","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/cure53/DOMPurify/commit/02724b8eb048dd219d6725b05c3000936f11d62d","https://github.com/cure53/DOMPurify/compare/2.0.16...2.0.17","https://lists.debian.org/debian-lts-announce/2020/10/msg00029.html","https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-26870","https://research.securitum.com/mutation-xss-via-mathml-mutation-dompurify-2-0-17-bypass/"],"products":["cure53:dompurify","debian:debian_linux","microsoft:visual_studio_2017","microsoft:visual_studio_2019","oracle:application_express"],"source":"nvd","synced_at":"2026-10-19T21:09:53.489947993+00:00"},"epss":{"cve":"CVE-2020-26870","score":0.04881,"percentile":0.92065,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-63q7-h895-m982","url":"https://osv.dev/vulnerability/GHSA-63q7-h895-m982","summary":"Cross-site Scripting in dompurify","modified":"2023-11-08T04:03:20.096890Z","packages":[{"ecosystem":"npm","name":"dompurify","purl":"pkg:npm/dompurify","ranges":["<2.0.17"],"fixed":["2.0.17"]}]}],"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."]}