CVE-2026-44040
Gravedad CVSS v3.1:
MEDIA
Tipo:
No Disponible / Otro tipo
Fecha de publicación:
01/07/2026
Última modificación:
01/07/2026
Descripción
*** Pendiente de traducción *** UltraVNC through 1.8.2.2 uses a cryptographically weak pseudo-random number generator to produce VNC authentication challenge bytes. In rfb/vncauth.c:119-129, the vncRandomBytes() function seeds libc rand() with time(0) + getpid() + rand() and generates a 16-byte challenge. The combined seed space is approximately 31 bits (libc rand() internal state) and is entirely determined by publicly-observable values (wall-clock time and process ID). An attacker who can observe the authentication exchange can enumerate the seed space and predict the challenge within seconds, enabling forgery or offline brute-forcing of responses. Note: on Windows, the active code path may use vncEncryptBytes2.cpp which calls CryptGenRandom; reachability on shipped Windows binaries requires compile-graph verification and is under investigation.
Impacto
Puntuación base 3.x
4.80
Gravedad 3.x
MEDIA