Open redirect via protocol-relative trailing-slash path
Published Aug 15, 2025 · Updated Aug 15, 2025
Open redirect in Astro before 9.4.1 allows remote attackers to send users to an external site through a crafted link. The Node adapter’s standalone static handler appends a slash and writes the resulting protocol-relative path to the Location header without rejecting internal-path syntax. Exploitation requires trailingSlash set to always and a user to follow the crafted link, enabling phishing through a trusted origin.
Summary
What happened
Open redirect in Astro before 9.4.1 allows remote attackers to send users to an external site through a crafted link. The Node adapter’s standalone static handler appends a slash and writes the resulting protocol-relative path to the Location header without rejecting internal-path syntax. Exploitation requires trailingSlash set to always and a user to follow the crafted link, enabling phishing through a trusted origin.
The record
- CVE
- CVE-2025-55207
- Published
- Aug 15, 2025
- Updated
- Aug 15, 2025
- Vendor
- Astro Technology Company
- Product
- Astro
- Classifications
- CWE-601, T1566.002, T1204.001
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 15, 2025CVE publishedPublication date reported by the CVE source.
- Aug 15, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 9.4.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Upstream standalone trailing-slash reproductionproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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