Next.js (< 15.5.21)

A vulnerability (CVE-2026-64645) in Next.js allows Server-Side Request Forgery (SSRF) and Open Redirect when `rewrites()` or `redirects()` rules in `next.config.js` use attacker-controlled input to construct external destination hostnames, enabling attackers to manipulate dynamic segments from the path or `has` captures to point the rewrite to an arbitrary hostname, potentially leading to internal network access, information disclosure, or redirection of users to malicious sites, affecting Next.js versions from 12.0.0 up to, but not including, 15.5.21, and versions from 16.0.0 up to, but not including, 16.2.11.