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CVE PROGRAM SOURCE RECORD2.1 Low

CVE-2026-59727

Astro: Cross-site scripting via unescaped transition:* directive values on hydrated islands

Description

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

withastro astro

  • >= 3.10.0, < 7.0.4affected

References