Astro is a web framework for content-driven websites. Prior to 7.3.2, Astro's JSX and MDX rendering pipeline treats string children of script and style elements as trusted HTML without distinguishing compiler-generated literal content from dynamic expression values. An application that passes attacker-controlled data directly as a dynamic child can allow a value containing a closing script or style tag to terminate the element and inject arbitrary HTML and JavaScript. Other JSX expression contexts escape dynamic strings automatically; the issue is limited to script and style children rendered through the astro:jsx renderer, including MDX components. Successful exploitation can produce reflected or stored cross-site scripting under the application's origin. This issue is fixed in 7.3.2.
CVE-2026-114127 is a low-severity cross-site scripting (XSS) vulnerability in the Astro web framework versions 7.1.0 through 7.3.2. It arises from improper neutralization of input in the server-side View Transition CSS generator, allowing attacker-controlled data to inject CSS rules into server-rendered pages. Although the vulnerability does not permit direct injection of HTML or JavaScript, the injected CSS can alter the page's appearance or expose data via DOM attributes. This issue is fixed in version 7.3.3.
CVE-2026-102984 is a high-severity vulnerability in the Astro web framework prior to version 11.1.3. The @astrojs/node adapter improperly builds request URLs from the Host header, and a malformed port can cause an invalid URL. This leads to an uncaught TypeError exception before routing begins. In the default configuration, this results in an HTTP 500 response while the server continues running. However, if staticHeaders is enabled, the uncaught exception causes the Node.js process to terminate, impacting availability. The vulnerability does not expose data or allow code execution. The issue is fixed in version 11.1.3.
Astro is a web framework for content-driven websites. From 5.2.0 until 8.2.4, the @astrojs/netlify adapter generates regular expressions for Netlify Image CDN remote-image allowlists without anchoring them to the beginning of the URL. Because Netlify evaluates these expressions with RegExp.test(), an allowed origin appearing only in a source URL's path or query can satisfy image.domains or image.remotePatterns while the URL's actual host remains attacker-controlled. An unauthenticated request to the public /.netlify/images endpoint can therefore cause the Image CDN to request attacker-selected URLs and may probe or reach internal services. Netlify egress protections may constrain reachable targets, and image transformation limits direct response exfiltration; no confidentiality or integrity impact has been demonstrated. This issue is fixed in version 8.2.4.
Astro is a web framework for content-driven websites. Prior to 7.2.4, Astro stripped a configured non-root base path from request pathnames using a string-prefix check without verifying a path-segment boundary. With base "/app", a request to "/appX/admin" resolved internally to the protected "/admin" route while middleware observed "/appX/admin" in context.url.pathname. In applications that authorize base-prefixed routes by inspecting context.url.pathname, an unauthenticated remote attacker could bypass pathname-based middleware authorization and reach protected routes. This issue is fixed in version 7.2.4.
CVE-2026-73424 is a medium severity vulnerability in the Astro web framework's Vercel adapter versions from 10.0.3 up to but not including 11.0.3. The issue allows unauthenticated GET requests to render routes that are intended to be protected by Vercel edge path rules or split edge middleware. This occurs because the adapter accepts the x_astro_path parameter for the public /_isr function based solely on the x-vercel-isr header, leading to unintended proxy or intermediary behavior (CWE-441). The vulnerability is fixed in version 11.0.3.
Astro is a web framework for content-driven websites. Prior to 8.1.2, the Astro Netlify adapter converts each image.remotePatterns entry into a regular expression written to .netlify/v1/config.json under images.remote_images for Netlify's Image CDN allowlist. In packages/integrations/netlify/src/index.ts, remotePatternToRegex() escapes dots in hostname values but interpolates literal pathname values without escaping regular expression metacharacters such as ., +, ?, (, and [, so a restrictive pathname such as /img/v1.0/file also matches metacharacter-adjacent paths, including paths that cross a segment. Netlify enforces the generated regular expression directly and Astro's matchPattern() helper does not revalidate the request, allowing optimization of images on an already-allowed host that the declared pathname was intended to exclude. This issue is fixed in version 8.1.2.
Astro is a web framework for content-driven websites. From 7.0.0 until 7.0.6, the composable astro/hono pipeline installs security.checkOrigin only through the middleware() primitive, while actions() and pages() can dispatch to user code independently. Mounting actions() before middleware(), as in the examples/advanced-routing example and Cloudflare Hono documentation, allows cross-origin form-encoded action requests to execute before the origin check, and using pages() without middleware() drops the check for on-demand endpoints and pages. The flaw enables blind write-only cross-site request forgery using the victim's cookies against ActionHandler.handle and PagesHandler.handleWithErrorFallback when manifest.checkOrigin is enabled; the attacker can trigger a state-mutating action or endpoint handler but cannot read the cross-origin response. The default non-composable astro() pipeline is not affected. This issue is fixed in version 7.0.6.
Astro is a web framework for content-driven websites. From 2.9.0 until 7.1.0, Astro's server-side View Transition CSS generator interpolates animation properties into an inline style element without escaping them for CSS and HTML contexts. An attacker-controlled View Transition animation value such as duration can terminate the generated style element and inject arbitrary HTML or JavaScript. The affected code is packages/astro/src/runtime/server/transition.ts; renderTransition passes sheet.toString() into markHTMLString(), while addAnimationProperty serializes duration through toTimeValue() and also handles easing, direction, delay, fillMode, and name. Exploitation requires an on-demand or server-rendered route to pass attacker-controlled data into a View Transition animation definition and can execute arbitrary JavaScript in the affected application's origin, allowing access to sensitive page data and authenticated actions available to the victim. This issue is fixed in version 7.1.0.
Astro is a web framework for content-driven websites. In versions 8.1.0 through 11.0.1, when trailingSlash: 'always' is configured, the @astrojs/node standalone server's static file handler appends a trailing slash to request paths and issues a 301 redirect. Paths beginning with /\ (slash-backslash) were not recognized as internal paths, so the handler would echo the raw path back in the Location header. Because browsers treat \ as / per the WHATWG URL specification, the resulting redirect could resolve to an external host. Preconditions for exploitation: trailingSlash: 'always' must be set (non-default; the default is 'ignore'), the request path must not have a file extension in its final segment, and an attacker must deliver the crafted link to a user. This issue has been fixed in version 11.0.2.
Astro is a web framework for content-driven websites. In versions 1.0.0 through 4.0.18, the source.title and enclosure.type item fields in packages/astro-rss/src/index.ts are interpolated directly into XML template strings without XML-character escaping before being parsed by fast-xml-parser. Both fields are validated only as z.string(), placing no restriction on XML special characters. An attacker who controls these values can inject arbitrary XML into the generated RSS feed: a value containing " can break out of an attribute (as with enclosure.type), and a value containing </source> can close an element early and inject additional nodes (as with source.title). This corrupts feed structure, injects false metadata (for example, a fake <link> pointing to a malicious URL), and can cause feed readers to misparse or display attacker-controlled content. In SSR mode (output: 'server'), the poisoned feed is served on every request to all subscribers. This issue has been fixed in version 4.0.19.
Astro is a web framework for content-driven websites. In versions 3.10.0 through 7.0.3, when a transition:persist, transition:scope, or transition:persist-props directive is applied to a client-hydrated (client:*) component, Astro copied the directive value onto the rendered <astro-island> element without HTML-escaping it. If a developer reflects attacker-controlled input into one of these directives, an attacker can break out of the attribute and inject arbitrary HTML/JavaScript into the server-rendered output, resulting in reflected cross-site scripting (XSS). Exploitation requires the application developer to have written a non-idiomatic pattern — passing untrusted, request-derived input directly into a transition directive. Astro applications that do not route untrusted input into these directives are unaffected. This issue has been fixed in version 7.0.4.
Astro is a web framework for content-driven websites. Versions prior to 7.0.6 are vulnerable to XSS through unescaped spread attribute names in renderHTMLElement. The fix for CVE-2026-54298 (GHSA-jrpj-wcv7-9fh9) added an INVALID_ATTR_NAME_CHAR guard to addAttribute() so that spread-prop attribute names containing "' >/= or whitespace are dropped. A second attribute-rendering path, renderHTMLElement() in packages/astro/src/runtime/server/render/dom.ts, has its own inline attribute loop that does not go through addAttribute() and was not updated. It interpolates the attribute name unescaped and only escapes the value, so untrusted prop keys spread onto a native-HTMLElement-subclass component can still break out of the attribute context. This issue has been fixed in version 7.0.6.
Astro is a web framework for content-driven websites. Version 6.4.7 performs authorization decisions on a partially decoded pathname after reaching the iterative URL decoder limit, while later rewrite route matching performs an additional decodeURI() operation and can resolve the request to a protected route. This issue is fixed in version 6.4.8.
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.
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. Astro versions prior to 6.1.10 used AES-GCM encryption to protect the confidentiality and integrity of server island props and slots parameters, but did not bind the ciphertext to its intended component or parameter type. An attacker could replay one component's encrypted props (p) value as another component's slots (s) value, or vice versa. Since slots contain raw unescaped HTML while props may contain user-controlled values, this could lead to XSS in applications. This occurs when the application uses server islands, two different server island components share the same key name for a prop and a slot, and an attacker has full control over the value of the overlapping prop (requires a dynamically rendered page). This vulnerability is fixed in 6.1.10.
@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.