CVE-2026-96629: AdminNeo: CSRF Token Secret Recoverable from Single Observed Token, Enabling Cross-Site Request Forgery

AdminNeo’s CSRF protection uses a BREACH-resistant XOR masking scheme, but the implementation transmits both the XOR mask and the masked value in every token. This allows any observer who sees a single CSRF token (via network sniffing, log files, Referrer header, or XSS) to instantly recover the session secret and forge unlimited valid CSRF tokens. Additionally, the underlying session token has only ~20 bits of entropy (rand(1, 1e6)), making blind brute-force feasible even without token observation.

Originally reported by @az0mb13 in Adminer: GHSA-q4f2-39gr-45jh