Astro is a web framework. Prior to version 5.15.8, a reflected XSS vulnerability is present when the server islands feature is used in the targeted application, regardless of what was intended by the component template(s). This issue has been patched in version 5.15.8.
https://github.com/withastro/astro/security/advisories/GHSA-wrwg-2hg8-v723
https://github.com/withastro/astro/commit/790d9425f39bbbb462f1c27615781cd965009f91