Astro is a web framework. Prior to version 5.14.2, Astro reflects the value in `X-Forwarded-Host` in output when using `Astro.url` without any validation. It is common for web servers such as nginx to route requests via the `Host` header, and forward on other request headers. As such as malicious request can be sent with both a `Host` header and an `X-Forwarded-Host` header where the values do not match and the `X-Forwarded-Host` header is malicious. Astro will then return the malicious value. This could result in any usages of the `Astro.url` value in code being manipulated by a request. For example if a user follows guidance and uses `Astro.url` for a canonical link the canonical link can be manipulated to another site. It is theoretically possible that the value could also be used as a login/registration or other form URL as well, resulting in potential redirecting of login credentials to a malicious party. As this is a per-request attack vector the surface area would only be to the malicious user until one considers that having a caching proxy is a common setup, in which case any page which is cached could persist the malicious value for subsequent users. Many other frameworks have an allowlist of domains to validate against, or do not have a case where the headers are reflected to avoid such issues. This could affect anyone using Astro in an on-demand/dynamic rendering mode behind a caching proxy. Version 5.14.2 contains a fix for the issue.
CVSS Score
6.5
EPSS Score
0.004
Published
2025-10-10
Astro is a web framework for content-driven websites. In versions of astro before 5.13.2 and 4.16.18, the image optimization endpoint in projects deployed with on-demand rendering allows images from unauthorized third-party domains to be served. On-demand rendered sites built with Astro include an /_image endpoint which returns optimized versions of images. A bug in impacted versions of astro allows an attacker to bypass the third-party domain restrictions by using a protocol-relative URL as the image source, e.g. /_image?href=//example.com/image.png. This vulnerability is fixed in 5.13.2 and 4.16.18.
CVSS Score
6.9
EPSS Score
0.006
Published
2025-08-19
Astro is a web framework for content-driven websites. In versions 5.2.0 through 5.12.7, there is an Open Redirect vulnerability in the trailing slash redirection logic when handling paths with double slashes. This allows an attacker to redirect users to arbitrary external domains by crafting URLs such as https://mydomain.com//malicious-site.com/. This increases the risk of phishing and other social engineering attacks. This affects sites that use on-demand rendering (SSR) with the Node or Cloudflare adapters. It does not affect static sites, or sites deployed to Netlify or Vercel. This issue is fixed in version 5.12.8. To work around this issue at the network level, block outgoing redirect responses with a Location header value that starts with `//`.
CVSS Score
5.5
EPSS Score
0.006
Published
2025-08-08
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