Requesting a static JS/CSS resource from the _astro path with an incorrect or malformed if-match header returns a 500 error with a one-year cache lifetime instead of 412 in some cases. As a result, all subsequent requests to that file — regardless of the if-match header — will be served a 5xx error instead of the file until the cache expires. Sending an incorrect or malformed if-match header should always …
Astro's Server Islands POST handler buffers and parses the full request body as JSON without enforcing a size limit. Because JSON.parse() allocates a V8 heap object for every element in the input, a crafted payload of many small JSON objects achieves ~15x memory amplification (wire bytes to heap bytes), allowing a single unauthenticated request to exhaust the process heap and crash the server. The /_server-islands/[name] route is registered on all …
A bug in Astro's image pipeline allows bypassing image.domains / image.remotePatterns restrictions, enabling the server to fetch content from unauthorized remote hosts.
Astro server actions have no default request body size limit, which can lead to memory exhaustion DoS. A single large POST to a valid action endpoint can crash the server process on memory-constrained deployments.
Server-Side Rendered pages that return an error with a prerendered custom error page (eg. 404.astro or 500.astro) are vulnerable to SSRF. If the Host: header is changed to an attacker's server, it will be fetched on /500.html and they can redirect this to any internal URL to read the response body through the first request.
In affected versions of astro, the image optimization endpoint in projects deployed with on-demand rendering allows images from unauthorized third-party domains to be served.
Following https://github.com/withastro/astro/security/advisories/GHSA-cq8c-xv66-36gw, there's still an Open Redirect vulnerability in a subset of Astro deployment scenarios.