CVE-2026-59730

Received Received - Intake

Path Traversal in Astro Node Standalone Server

Publication date: 2026-07-27

Last updated on: 2026-07-27

Assigner: GitHub, Inc.

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 Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-07-27

Last Modified

2026-07-27

Generated

2026-07-28

AI Q&A

2026-07-28

EPSS Evaluated

N/A

NVD

CVE-2026-59730

EUVD

EUVD-2026-49586

Affected Vendors & Products

Vendor	Product	Version / Range
astro	astro	From 8.1.0 (inc) to 11.0.1 (inc)
astro	astro	11.0.2

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-601	The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.

Attack-Flow Graph

Executive Summary

This vulnerability in Astro versions 8.1.0 through 11.0.1 involves a misconfiguration in the @astrojs/node standalone server. When trailingSlash: 'always' is set, the server incorrectly handles paths starting with /\ (slash-backslash) by echoing them back in a 301 redirect Location header. Browsers interpret \ as /, potentially redirecting users to an external host instead of an internal path.

Detection Guidance

Check Astro configuration files for trailingSlash: 'always' setting. Inspect server logs for 301 redirects with unusual Location headers containing backslashes. No specific commands are provided in the context.

Impact Analysis

An attacker could craft a malicious link with a path starting with /\ and trick users into clicking it. If the user's browser follows the redirect, they may be sent to an unintended external website, potentially leading to phishing attacks, malware downloads, or exposure to malicious content. This requires the user to click the link and the server to have trailingSlash: 'always' configured.

Mitigation Strategies

Upgrade Astro to version 11.0.2 or later. If upgrading is not possible, change the trailingSlash configuration from 'always' to 'ignore' in your Astro config file.

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