CVE-2025-50579: JC21 Nginx Proxy Manager

Medium severity, CVSS 5.3. EPSS: 0.4% chance of exploitation in the next 30 days.

A CORS misconfiguration in Nginx Proxy Manager v2.12.3 allows unauthorized domains to access sensitive data, particularly JWT tokens, due to improper validation of the Origin header. This misconfiguration enables attackers to intercept tokens using a simple browser script and exfiltrate them to a remote attacker-controlled server, potentially leading to unauthorized actions within the application.

Affected products

• JC21 Nginx Proxy Manager: version 2.12.3 only

Published 2025-08-19. Last modified 2026-06-17.