Internal response disclosure via Host-derived error fetch
Published Feb 24, 2026 · Updated Feb 24, 2026
SSRF in Astro before 9.5.4 allows remote attackers to read internal HTTP responses through a Host-controlled custom error-page fetch. Astro's renderError path builds statusURL from the request-derived base URL, and prerenderedErrorPageFetch follows redirects and returns the fetched body and headers. Exploitation requires a directly reachable SSR deployment with a prerendered custom error page and no Host header validation.
Summary
What happened
SSRF in Astro before 9.5.4 allows remote attackers to read internal HTTP responses through a Host-controlled custom error-page fetch. Astro's renderError path builds statusURL from the request-derived base URL, and prerenderedErrorPageFetch follows redirects and returns the fetched body and headers. Exploitation requires a directly reachable SSR deployment with a prerendered custom error page and no Host header validation.
The record
- CVE
- CVE-2026-25545
- Published
- Feb 24, 2026
- Updated
- Feb 24, 2026
- Vendor
- Astro Technology Company
- Product
- Astro
- Classifications
- CWE-918, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 24, 2026CVE publishedPublication date reported by the CVE source.
- Feb 24, 2026Record 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=< 9.5.4
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
- GHSA-qq67-mvv5-fw3g proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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