CVE-2026-59730
LowCVSS 2.1Exploitation Probability (EPSS)
Low risk29th percentile - higher than 29% of all known CVEs
Summary
In Astro 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.
Risk Assessment
An attacker can exploit this vulnerability to redirect users to malicious sites, potentially leading to data theft or malware infection.
Recommendation
Update Astro to version 11.0.2 or later, which contains the fix for this vulnerability.
Original NVD description (English source)
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.