{"id":"CVE-2026-66829","summary":"html_sanitize_ex HTML5 scrubber keeps attacker-supplied meta refresh, allowing forced cross-origin redirection","details":"URL 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 \u003cmeta http-equiv=\"refresh\"\u003e element in sanitized HTML. HtmlSanitizeEx.html5/1 keeps attacker-supplied \u003cmeta\u003e 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.","aliases":["EEF-CVE-2026-66829","GHSA-2c6f-3j54-xpcr"],"modified":"2026-08-09T03:30:48.670405500Z","published":"2026-08-06T14:49:23.468Z","database_specific":{"cwe_ids":["CWE-601"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66829.json","unresolved_ranges":[{"source":"AFFECTED_FIELD","extracted_events":[{"introduced":"8976d64ea0b77d26093a94a43ec48a3978e8d028"},{"fixed":"9f7e38be51edc38f132dfe994f37af5cf5e0e76f"}]}],"cna_assigner":"EEF"},"references":[{"type":"WEB","url":"https://cna.erlef.org/cves/CVE-2026-66829.html"},{"type":"WEB","url":"https://github.com"},{"type":"WEB","url":"https://osv.dev/vulnerability/EEF-CVE-2026-66829"},{"type":"WEB","url":"https://repo.hex.pm"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66829.json"},{"type":"ADVISORY","url":"https://github.com/rrrene/html_sanitize_ex/security/advisories/GHSA-2c6f-3j54-xpcr"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-66829"},{"type":"FIX","url":"https://github.com/rrrene/html_sanitize_ex/commit/9f7e38be51edc38f132dfe994f37af5cf5e0e76f"},{"type":"PACKAGE","url":"https://github.com/rrrene/html_sanitize_ex"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/rrrene/html_sanitize_ex","events":[{"introduced":"088f92b18a4a3911a862b527d5eb3713f9abac24"},{"fixed":"f25255c82a3c6034a57d934718e10c982d29fa31"},{"fixed":"9f7e38be51edc38f132dfe994f37af5cf5e0e76f"}],"database_specific":{"source":["DESCRIPTION","REFERENCES"],"extracted_events":[{"introduced":"0.3.1"},{"fixed":"1.5.3"}]}}],"versions":["v1.5.2","v1.5.1","v1.5.0","v1.5.0-rc.0","v1.4.4","v1.4.3","v1.4.2","v1.4.1","v1.2.0","v1.0.1","v1.0.0","v0.3.1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-66829.json"}}],"schema_version":"1.8.0","severity":[{"type":"CVSS_V4","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"}]}