The adapter in Astro’s @astrojs/netlify package generates regular expressions for Netlify’s Image CDN allowlist that are not anchored at the start of the URL. This flaw allows a host that is only present in a path or query parameter to satisfy the allowlist while the actual host remains attacker‑controlled, enabling the Image CDN to fetch malicious URLs. An unauthenticated request to the public /.netlify/images endpoint can trigger the CDN to reach attacker‑selected destinations, potentially probing internal networks. Although no evidence of data exfiltration or modification exists, the vulnerability represents a server‑side request forgery (SSRF) that could expose internal resources. The weakness is classified as CWE‑625 and CWE‑918.

Users deploying Astro web sites with the @astrojs/netlify adapter between versions 5.2.0 and 8.2.4 are affected. The issue is fixed in release 8.2.4 and later.

The vulnerability scores a CVSS of 6.3, indicating moderate severity, and it is not listed on the CISA KEV catalog. Exploitation requires only an unauthenticated HTTP request to the public endpoint, making it easy to trigger. The attacker can choose arbitrary external URLs, potentially reaching internal services. Because the adapter is publicly exposed, the risk is readily exploitable without special privileges or credentials.