CVE-2026-35408: Directus: Missing Cross-Origin Opener Policy

Directus’s Single Sign-On (SSO) login pages lacked a Cross-Origin-Opener-Policy (COOP) HTTP response header. Without this header, a malicious cross-origin window that opens the Directus login page retains the ability to access and manipulate the window object of that page. An attacker can exploit this to intercept and redirect the OAuth authorization flow to an attacker-controlled OAuth client, causing the victim to unknowingly grant access to their authentication provider account (e.g. Google, Discord).