CVE-2026-50146: Astro

Medium severity, CVSS 6.1. EPSS: 0.3% chance of exploitation in the next 30 days.

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

• Astro Astro: before 6.3.3 (fixed in 6.3.3)

Published 2026-06-22. Last modified 2026-06-23.