{"id":"CVE-2026-59923","aliases":["GHSA-8c25-4j27-2rv3","PYSEC-2026-2211"],"url":"https://o3.security/vulnerability/CVE-2026-59923","summary":"Mistune: XSS via percent-encoded javascript URI bypass in safe_url()","details":"Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, HTMLRenderer.safe_url() does not block percent-encoded javascript URIs, allowing attacker-supplied Markdown links or images to bypass URL protections and execute script in rendered HTML. This issue is fixed in version 3.3.0.","published":"2026-07-08T16:14:39.266Z","modified":"2026-08-12T03:51:18.978170788Z","cvss":{"score":6.1,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"},"epss":{"score":0.00348,"percentile":0.27803,"asOf":"2026-09-07"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"mistune","fixedVersion":"3.3.0"}],"fix":{"url":"https://github.com/lepture/mistune/commit/c7101fcbb6e8790e8e39157c5ca2238fc6dd6cbc","label":"lepture/mistune@c7101fc"},"references":[{"type":"WEB","url":"https://github.com/lepture/mistune/releases/tag/v3.3.0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59923.json"},{"type":"ADVISORY","url":"https://github.com/lepture/mistune/security/advisories/GHSA-8c25-4j27-2rv3"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59923"},{"type":"FIX","url":"https://github.com/lepture/mistune/commit/c7101fcbb6e8790e8e39157c5ca2238fc6dd6cbc"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:18.978170788Z"}}