Critical (9.8). EPSS 3.9% chance of exploitation in the next 30 days.
UltraVNC revision 1211 has multiple off-by-one vulnerabilities in VNC server code, which can potentially result in code execution. This attack appears to be exploitable via network connectivity. These vulnerabilities have been fixed in revision 1212.
Severity
CVSS 3.1
9.8 critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
3.9% chance of exploitation in the next 30 days; higher than 90% of CVEs (scores of 2026-10-31)