Search: CVE-2026-22031

CVE-2026-22031 is a high-severity vulnerability in the @fastify/middie plugin prior to version 9.1.0 that allows bypassing middleware protections via URL-encoded path prefixes. The middleware fails to decode URL-encoded characters when matching paths, while Fastify's router correctly decodes them, enabling attackers to access protected routes without middleware enforcement. This can lead to unauthorized access, compromising confidentiality and integrity of applications using vulnerable versions. The vulnerability requires network access and low privileges but no user interaction. Although no known exploits are reported, the impact on affected systems is significant. Upgrading to version 9.1.0 or later mitigates the issue.