medium6.1
CVE-2026-41067
Astro: XSS in define:vars via incomplete </script> tag sanitization
Impact
Astro is a web framework. Prior to 6.1.6, the defineScriptVars function in Astro's server-side rendering pipeline uses a case-sensitive regex /<\/script>/g to sanitize values injected into inline <script> tags via the define:vars directive. HTML parsers close <script> elements case-insensitively and also accept whitespace or / before the closing >, allowing an attacker to bypass the sanitization with payloads like </Script>, </script >, or </script/> and inject arbitrary HTML/JavaScript. This vulnerability is fixed in 6.1.6.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| npm | astro | < 6.1.6 | 6.1.6 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Astro | Astro | before 6.1.6 |