{"affected":[{"package":{"ecosystem":"Hex","name":"html_sanitize_ex","purl":"pkg:hex/html_sanitize_ex"},"ranges":[{"events":[{"introduced":"0.3.1"},{"fixed":"1.5.3"}],"type":"SEMVER"}],"versions":["0.3.1","1.0.0","1.0.1","1.1.0-rc1","1.1.0","1.1.1","1.2.0","1.3.0-rc1","1.3.0-rc2","1.3.0-rc3","1.3.0","1.4.0","1.4.1","1.4.2","1.4.3","1.4.4-rc.0","1.4.4","1.5.0-rc.0","1.5.0","1.5.1","1.5.2"]},{"ranges":[{"events":[{"introduced":"8976d64ea0b77d26093a94a43ec48a3978e8d028"},{"fixed":"9f7e38be51edc38f132dfe994f37af5cf5e0e76f"}],"repo":"https://github.com/rrrene/html_sanitize_ex","type":"GIT"}]}],"aliases":["GHSA-2c6f-3j54-xpcr","CVE-2026-66829"],"credits":[{"name":"Peter Ullrich","type":"FINDER"},{"name":"Jonatan Männchen / EEF","type":"ANALYST"},{"name":"René Föhring","type":"REMEDIATION_DEVELOPER"}],"database_specific":{"capec_ids":["CAPEC-154"],"cpe_ids":["cpe:2.3:a:rrrene:html_sanitize_ex:*:*:*:*:*:*:*:*"],"cwe_ids":["CWE-601"]},"details":"## Summary\n\nURL Redirection to Untrusted Site ('Open Redirect') vulnerability in the HTML5 scrubber in rrrene html\\_sanitize\\_ex allows a remote attacker to force visitors of a page to navigate to a site of the attacker's choosing via a <meta http-equiv=\"refresh\"> element in sanitized HTML. HtmlSanitizeEx.html5/1 keeps attacker-supplied <meta> elements in its output. A meta element acts on the whole document rather than on the fragment it was embedded in, so it can also declare document-wide directives such as Content-Security-Policy.\n\nThis is not cross-site scripting. Browsers do not navigate a meta refresh to a javascript: URL, so the uppercase JAVASCRIPT: filter bypass yields no script execution and none was demonstrated.\n\nThis issue affects html\\_sanitize\\_ex: from 0.3.1 before 1.5.3.\n\n## Workaround\n\nSanitize with basic\\_html/1, markdown\\_html/1 or strip\\_tags/1, none of which allow meta, or define a custom scrubber that omits it.\n\n## Configuration\n\nOnly HtmlSanitizeEx.html5/1, and custom scrubbers declared with use HtmlSanitizeEx, extend: :html5, allow the meta element, and the sanitized output must be rendered to other users.","id":"EEF-CVE-2026-66829","modified":"2026-08-06T14:49:24.419579Z","published":"2026-08-06T14:49:23.468Z","references":[{"type":"ADVISORY","url":"https://github.com/rrrene/html_sanitize_ex/security/advisories/GHSA-2c6f-3j54-xpcr"},{"type":"WEB","url":"https://cna.erlef.org/cves/CVE-2026-66829.html"},{"type":"FIX","url":"https://github.com/rrrene/html_sanitize_ex/commit/9f7e38be51edc38f132dfe994f37af5cf5e0e76f"},{"type":"PACKAGE","url":"https://hex.pm/packages/html_sanitize_ex"}],"related":[],"schema_version":"1.7.3","severity":[{"score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N","type":"CVSS_V4"}],"summary":"html_sanitize_ex HTML5 scrubber keeps attacker-supplied meta refresh, allowing forced cross-origin redirection","upstream":[]}