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OpenAdvisories
High · 7.1 CVE-2026-50146 EUVD-2026-38335GHSA-8hv8-536x-4wqp

Astro: Reflected XSS via unescaped slot name

Published Jun 22, 2026 · Updated Jun 23, 2026 · Assigned by GitHub_M

Description

Astro is a web framework. Prior to 6.3.3, when a component uses a client:* directive, Astro inserts named slot content into a data-astro-template attribute without HTML escaping the slot name allowing an attacker to break out of the attribute context and inject arbitrary HTML, resulting in reflected XSS during SSR. This vulnerability is fixed in 6.3.3.

Affected products

VendorProductAffectedFixed
withastro astro < 6.3.3 —

Affected packages

EcosystemPackageAffectedFixedRecord
npm astro < 6.3.3 6.3.3 GHSA-8hv8-536x-4wqp

References