UltraVNC is a free and open source remote pc access software. A vulnerability has been found in versions prior to 1.3.8.0 in which the DSM plugin module, which allows a local authenticated user to achieve local privilege escalation (LPE) on a vulnerable system. The vulnerability has been fixed to allow loading of plugins from the installed directory. Affected users should upgrade their UltraVNC to 1.3.8.1. Users unable to upgrade should not install and run UltraVNC server as a service. It is advisable to create a scheduled task on a low privilege account to launch WinVNC.exe instead. There are no known workarounds if winvnc needs to be started as a service.

Axeda agent (All versions) and Axeda Desktop Server for Windows (All versions) uses hard-coded credentials for its UltraVNC installation. Successful exploitation of this vulnerability could allow a remote authenticated attacker to take full remote control of the host operating system.

UltraVNC revision 1211 contains multiple memory leaks (CWE-665) in VNC server code, which allows an attacker to read stack memory and can be abused for information disclosure. Combined with another vulnerability, it can be used to leak stack memory and bypass ASLR. This attack appears to be exploitable via network connectivity. These vulnerabilities have been fixed in revision 1212.

UltraVNC revision 1206 has multiple off-by-one vulnerabilities in VNC client code connected with improper usage of ClientConnection::ReadString function, which can potentially result code execution. This attack appears to be exploitable via network connectivity. These vulnerabilities have been fixed in revision 1207.

UltraVNC revision 1211 has a stack buffer overflow vulnerability in VNC server code inside file transfer request handler, which can result in Denial of Service (DoS). This attack appears to be exploitable via network connectivity. This vulnerability has been fixed in revision 1212.

UltraVNC revision 1211 has a heap buffer overflow vulnerability in VNC server code inside file transfer request handler, which can potentially result in code execution. This attack appears to be exploitable via network connectivity. This vulnerability has been fixed in revision 1212.

UltraVNC revision 1203 has out-of-bounds access vulnerability in VNC client inside Ultra2 decoder, which can potentially result in code execution. This attack appears to be exploitable via network connectivity. This vulnerability has been fixed in revision 1204.

UltraVNC revision 1211 has a heap buffer overflow vulnerability in VNC server code inside file transfer handler, which can potentially result code execution. This attack appears to be exploitable via network connectivity. This vulnerability has been fixed in revision 1212.

UltraVNC revision 1211 has a heap buffer overflow vulnerability in VNC server code inside file transfer offer handler, which can potentially in result code execution. This attack appears to be exploitable via network connectivity. This vulnerability has been fixed in revision 1212.

UltraVNC revision 1207 has out-of-bounds read vulnerability in VNC client code inside TextChat module, which results in a denial of service (DoS) condition. This attack appears to be exploitable via network connectivity. This vulnerability has been fixed in revision 1208.