{"id":"CVE-2026-73490","aliases":["GHSA-9wjq-cp2p-hrgf"],"url":"https://o3.security/vulnerability/CVE-2026-73490","summary":"Loofah: SVG `href` attribute bypasses local-reference restriction","details":"## Summary\n\nLoofah's HTML5 sanitizer restricted only the `xlink:href` attribute on certain SVG elements to local, same-document references. Browsers also accept a plain `href` attribute as an alternative to the deprecated `xlink:href` per the SVG 2 spec, but Loofah did not apply the same restriction to it, allowing those elements to reference arbitrary external documents.\n\n## Impact\n\nSVG `<use>` can load and render external SVG content by reference. If the referenced external SVG is same-origin and contains scripts or other dangerous content, it could execute in the context of the sanitized document. `<feImage>` can load external images, which can be used for tracking. Modern browsers restrict cross-origin `<use>` fetches, which limits but does not eliminate the risk.\n\nApplications that sanitize user-supplied SVG (directly, or as part of HTML) with Loofah's default allowlist are affected.\n\n## Mitigation\n\nUpgrade to Loofah >= 2.25.2.\n\n## Credit\n\nFound by the maintainer, Mike Dalessio, during a security audit.","published":"2026-08-12T20:58:12.219Z","modified":"2026-09-11T03:48:36.723502603Z","cvss":{"score":4.7,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N"},"epss":{"score":0.0018,"percentile":0.07788,"asOf":"2026-09-15"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"RubyGems","name":"loofah","fixedVersion":"2.25.2"}],"fix":{"url":"https://github.com/flavorjones/loofah/commit/20867b9be689521887364b74822c41ef830523c9","label":"flavorjones/loofah@20867b9"},"references":[{"type":"WEB","url":"https://github.com/flavorjones/loofah/releases/tag/v2.25.2"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/73xxx/CVE-2026-73490.json"},{"type":"ADVISORY","url":"https://github.com/flavorjones/loofah/security/advisories/GHSA-9wjq-cp2p-hrgf"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-73490"},{"type":"FIX","url":"https://github.com/flavorjones/loofah/commit/20867b9be689521887364b74822c41ef830523c9"},{"type":"FIX","url":"https://github.com/flavorjones/loofah/pull/308"},{"type":"PACKAGE","url":"https://github.com/flavorjones/loofah"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-11T03:48:36.723502603Z"}}