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HIGH

CVE-2026-25545

Astro has Full-Read SSRF in error rendering via Host: header injection

CVSS v3

8.6

HIGH

EPSS Score

5.2 %

exploit probability

CISA KEV

No

known exploited

Exploitation

poc

SSVC status

Description

Astro is a web framework. Prior to version 9.5.4, Server-Side Rendered pages that return an error with a prerendered custom error page (eg. `404.astro` or `500.astro`) are vulnerable to SSRF. If the `Host:` header is changed to an attacker's server, it will be fetched on `/500.html` and they can redirect this to any internal URL to read the response body through the first request. An attacker who can access the application without `Host:` header validation (eg. through finding the origin IP behi

Technical details

CVSS v3 Vector
3.1
Published
2026-02-24
Last Modified
2026-02-25

Frequently asked questions

What is CVE-2026-25545?

Astro is a web framework. Prior to version 9.5.4, Server-Side Rendered pages that return an error with a prerendered custom error page (eg. `404.astro` or `500.astro`) are vulnerable to SSRF. If the `Host:` header is changed to an attacker's server, it will be fetched on `/500.html` and they can redirect this to any internal URL to read the response body through the first request. An attacker who can access the application without `Host:` header validation (eg. through finding the origin IP behi

Is CVE-2026-25545 actively exploited?

A proof-of-concept exploit exists for CVE-2026-25545, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2026-25545?

CVE-2026-25545 has a CVSS v3 base score of 8.6 (HIGH severity), with vector string 3.1.

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