CVE-2026-25545 Scanner

Astro SSR is a static site generator designed for modern web applications, enabling developers to create fast and optimized static content. It is utilized by web developers and companies for building performant websites that require server-side rendering. Offering seamless integrations with modern JavaScript frameworks, Astro is ideal for static site deployments and complex web applications. Companies focusing on high-performance web solutions often choose Astro for its flexibility and ease of use. Industries including e-commerce, tech startups, and digital agencies leverage Astro to maintain agility in web development. Its wide adoption is due to its ability to handle large-scale content effectively with minimal load times.

The vulnerability in Astro SSR, identified as Server-Side Request Forgery (SSRF), occurs due to improper Host header validation on error page rendering. This SSRF vulnerability can be exploited to redirect requests to internal resources, which poses significant security risks. Attackers can leverage this vulnerability to access sensitive endpoints like cloud metadata services unauthorisedly. By redirecting requests through the server, malicious entities can exploit backend resources without detection. The vulnerability is severe due to the low level of skill required to execute an exploit and the potential impact on confidentiality. Addressing this vulnerability promptly is crucial to maintaining infrastructure security.

Technical details about this SSRF vulnerability involve improper validation of the Host header in error page rendering, which facilitates full-read exploitation. This flaw allows attackers to bypass normal access controls and interact with internal services through crafted requests. The risk is amplified by the fact that an attacker can reach environment files, metadata endpoints, and any host accessible by the server. Details indicate that patching the systems by upgrading to secure versions, which involve error handling changes, mitigates the risk. This vulnerability impacts environments where Astro is employed for backend and API integrations. Ensuring the validation of incoming host headers is essential to neutralize this attack vector.

Exploitation of this vulnerability can have dire consequences, including unauthorized access to internal services and sensitive data exposure. Attackers could leverage this flaw to gain insights into cloud-based environments, potentially breaching security perimeters. Unauthorized access to metadata endpoints might allow attackers to execute subsequent attacks on cloud infrastructure. The compromise of environment files could lead to the exposure of sensitive configuration data, thereby escalating the scope of potential breaches. Overarching effects encompass data leakage, unauthorized service access, and potential full-scale network compromise. Mitigating such risks requires immediate attention and strategic remediation.

REFERENCES

• https://github.com/withastro/astro/security/advisories/GHSA-qq67-mvv5-fw3g
• https://github.com/withastro/astro/pull/15473
• https://nvd.nist.gov/vuln/detail/CVE-2026-25545