EUVD-2026-40882

UltraVNC through 1.8.2.2 uses inadequate cryptography in the MS-Logon II authentication scheme rfbUltraVNCMsLogonIIAuth. In rfb/dh.cpp the Diffie-Hellman key exchange is performed with parameters that fit in an unsigned 64-bit integer DHMAXBITS controls the prime size. A 64-bit DH key can be brok...