{"id":"CVE-2026-59727","aliases":["GHSA-7pw4-f3q4-r2p2"],"url":"https://o3.security/vulnerability/CVE-2026-59727","summary":"Astro: Cross-site scripting via unescaped transition:* directive values on hydrated islands","details":"Astro is a web framework for content-driven websites. In versions 3.10.0 through 7.0.3, when a transition:persist, transition:scope, or transition:persist-props directive is applied to a client-hydrated (client:*) component, Astro copied the directive value onto the rendered <astro-island> element without HTML-escaping it. If a developer reflects attacker-controlled input into one of these directives, an attacker can break out of the attribute and inject arbitrary HTML/JavaScript into the server-rendered output, resulting in reflected cross-site scripting (XSS). Exploitation requires the application developer to have written a non-idiomatic pattern — passing untrusted, request-derived input directly into a transition directive. Astro applications that do not route untrusted input into these directives are unaffected. This issue has been fixed in version 7.0.4.","published":"2026-07-27T19:42:32.222Z","modified":"2026-08-12T03:51:37.050955830Z","cvss":null,"epss":{"score":0.0031,"percentile":0.23405,"asOf":"2026-09-07"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"astro","fixedVersion":"7.0.4"}],"fix":{"url":"https://github.com/withastro/astro/commit/7ba0bb1dc7516e88caff9abd7767322af44b0294","label":"withastro/astro@7ba0bb1"},"references":[{"type":"WEB","url":"https://github.com/withastro/astro/releases/tag/astro@7.0.4"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59727.json"},{"type":"ADVISORY","url":"https://github.com/withastro/astro/security/advisories/GHSA-7pw4-f3q4-r2p2"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59727"},{"type":"FIX","url":"https://github.com/withastro/astro/commit/7ba0bb1dc7516e88caff9abd7767322af44b0294"},{"type":"FIX","url":"https://github.com/withastro/astro/pull/17212"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:37.050955830Z"}}