Astro is a web framework. Prior to 6.4.6, the spreadAttributes function in Astro's server-side rendering pipeline iterates over object keys and passes them directly to addAttribute, which interpolates the key into the HTML output without escaping. When a developer uses the spread syntax {...props} on an HTML element and the object keys come from an untrusted source (API, CMS, URL parameters), an attacker can inject arbitrary HTML attributes including event handlers like onmousemove, onclick, or break out of the attribute context entirely to inject new elements. This vulnerability is fixed in 6.4.6.

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.

@astrojs/netlify is an adapter that allows Astro to deploy your hybrid or server rendered site to Netlify. Prior to 7.0.13, @astrojs/netlify converts Astro image.remotePatterns into Netlify Image CDN images.remote_images regular expressions with broader semantics than Astro's canonical matcher. A single wildcard hostname such as *.example.com is converted to an optional subdomain regex, so the apex host matches. A single wildcard pathname such as /ok/* is converted without end anchoring, so deeper paths match by prefix. This vulnerability is fixed in 7.0.13.

Astro is a web framework. Prior to 6.4.6, Astro SSR apps with prerendered error pages (/404 or /500 using export const prerender = true) fetch those pages over HTTP at runtime when an error occurs. The URL for this fetch is derived from request.url, which in turn gets its origin from the incoming Host header. When the Host header is not validated against allowedDomains, an attacker can point the fetch at an arbitrary host and read the response. This vulnerability is fixed in 6.4.6.

@astrojs/node allows Astro to deploy your SSR site to Node targets. Prior to 10.0.5, requesting a static js/css resources from _astro path with an incorrect/malformed if-match header returns a 500 error with a one year cache lifetime instead of 412 in some cases. This has the effect that all subsequent requests to that file, regardless of if-match header will be served a 5xx error instead of the file until the cache expires. This vulnerability is fixed in 10.0.5.

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.