UltraVNC Repeater before 1300 does not restrict destination IP addresses or TCP ports, which allows remote attackers to obtain open-proxy functionality by using a :: substring in between the IP address and port number.
Severity
CVSS 3.0
7.5 high
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
EPSS
1.9% chance of exploitation in the next 30 days; higher than 79% of CVEs (scores of 2026-10-31)