UltraVNC revision 1199 has a out-of-bounds read vulnerability in VNC code inside client CoRRE decoder, caused by multiplication overflow. This attack appears to be exploitable via network connectivity. This vulnerability has been fixed in revision 1200.
Severity
CVSS 3.0
9.8 critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
2.2% chance of exploitation in the next 30 days; higher than 82% of CVEs (scores of 2026-10-31)