CVE-2026-59730: CWE-601: URL Redirection to Untrusted Site ('Open Redirect') in withastro astro
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.
AI Analysis
Technical Summary
The vulnerability (CVE-2026-59730) in the Astro web framework affects versions 8.1.0 through 11.0.1 when configured with trailingSlash: 'always'. The @astrojs/node standalone server's static file handler appends a trailing slash and issues a 301 redirect. However, paths starting with a slash followed by a backslash ("/\") are not recognized as internal, causing the handler to reflect the raw path in the Location header. Because browsers treat backslashes as forward slashes, this can lead to an open redirect to an external host. Exploitation requires the trailingSlash setting, a crafted path without a file extension, and user interaction. The vulnerability is resolved in version 11.0.2.
Potential Impact
An attacker can craft a URL that causes the server to redirect users to an external, potentially malicious site due to improper handling of certain path formats. This open redirect vulnerability can be used in phishing attacks or to bypass security filters relying on URL validation. The CVSS score is low (2.1), reflecting limited impact and the need for user interaction and specific configuration.
Mitigation Recommendations
Upgrade Astro to version 11.0.2 or later, where this open redirect vulnerability is fixed. If upgrading is not immediately possible, avoid using the trailingSlash: 'always' configuration in the @astrojs/node standalone server to prevent exposure. Monitor vendor advisories for any additional guidance.
CVE-2026-59730: CWE-601: URL Redirection to Untrusted Site ('Open Redirect') in withastro astro
Description
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.
CVSS v4.0
Score 2.1low
Affected software
withastro
astro
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability (CVE-2026-59730) in the Astro web framework affects versions 8.1.0 through 11.0.1 when configured with trailingSlash: 'always'. The @astrojs/node standalone server's static file handler appends a trailing slash and issues a 301 redirect. However, paths starting with a slash followed by a backslash ("/\") are not recognized as internal, causing the handler to reflect the raw path in the Location header. Because browsers treat backslashes as forward slashes, this can lead to an open redirect to an external host. Exploitation requires the trailingSlash setting, a crafted path without a file extension, and user interaction. The vulnerability is resolved in version 11.0.2.
Potential Impact
An attacker can craft a URL that causes the server to redirect users to an external, potentially malicious site due to improper handling of certain path formats. This open redirect vulnerability can be used in phishing attacks or to bypass security filters relying on URL validation. The CVSS score is low (2.1), reflecting limited impact and the need for user interaction and specific configuration.
Mitigation Recommendations
Upgrade Astro to version 11.0.2 or later, where this open redirect vulnerability is fixed. If upgrading is not immediately possible, avoid using the trailingSlash: 'always' configuration in the @astrojs/node standalone server to prevent exposure. Monitor vendor advisories for any additional guidance.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-07-06T15:34:16.917Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a67c1be9c2644c7f8cb1245
Added to database: 07/27/2026, 20:38:22 UTC
Last enriched: 07/29/2026, 23:55:43 UTC
Last updated: 09/11/2026, 07:31:54 UTC
Views: 72
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