Server-Side Request Forgery Vulnerability in Astro Web Framework

CVE-2026-25545

What is CVE-2026-25545?

CVE-2026-25545 is a critical vulnerability found in the Astro Web Framework, specifically before version 9.5.4. Astro serves as a web framework designed for building modern websites, allowing developers to create server-side rendered applications efficiently. This vulnerability arises from a Server-Side Request Forgery (SSRF) issue affecting server-rendered error pages such as 404.astro and 500.astro. If an attacker manages to manipulate the Host: header of an incoming request, they can redirect the framework to fetch data from any internal URL, leveraging the server’s own capabilities to make requests to restricted areas of the network. This exploitation can lead to unauthorized access to sensitive resources, particularly if the attacker knows how to access the server directly without protection measures like proxy validation.

Potential impact of CVE-2026-25545

1. Unauthorized Data Access: An attacker could exploit this vulnerability to gain access to sensitive internal services or databases, extracting confidential information that could lead to data breaches.

2. Network Exposure: By leveraging SSRF, malicious actors can probe internal networks and detect services running on private IPs, potentially expanding their attack surface dramatically and allowing for lateral movement within the network.

3. Service Disruption: The ability to redirect server requests could allow attackers to create denial-of-service conditions by overwhelming internal resources or causing applications to behave unpredictably.

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References