Executive brief
The @astrojs/netlify integration generates an image content allowlist for Netlify's Image CDN based on security patterns defined by developers. Due to improper escaping of special characters in URL paths, the allowlist becomes overly permissive and accepts image URLs that should have been blocked. An attacker with access to alternative image paths on the same host (using characters like dots or other regex metacharacters) could potentially optimize images through the CDN that the developer intended to exclude.
Technical details
The vulnerability is an improper regex escape issue in the remotePatternToRegex() function in packages/integrations/netlify/src/index.ts. The function correctly escapes dots in the hostname component but fails to escape regex metacharacters (such as . + ? [ ( etc.) in the literal pathname component before interpolating it into a regular expression. This causes unintended pathname broadening: for example, a pathname pattern /img/v1.0/file will incorrectly match /img/v1X0/file because the unescaped dot matches any character, and can even match forward slashes crossing path segments. The security boundary is the generated regex itself, enforced directly by Netlify's Image CDN with no compensating validation layer. The fix escapes all metacharacters in literal path portions before regex interpolation and has been shipped in version 8.1.2.
Affected products
- Astro @astrojs/netlify <=8.1.1
Timeline
- 2026-07-20: disclosed
- 2026-07-15: patched: fix available in version 8.1.2