A DLL side loading vulnerability in the Windows Service in TeamViewer versions up to 11.0.133222 (fixed in 11.0.214397), 12.0.181268 (fixed in 12.0.214399), 13.2.36215 (fixed in 13.2.36216), and 14.6.4835 (fixed in 14.7.1965) on Windows could allow an attacker to perform code execution on a target system via a service restart where the DLL was previously installed with administrative privileges. Exploitation requires that an attacker be able to create a new file in the TeamViewer application directory; directory permissions restrict that by default.

An issue was discovered in TeamViewer 14.2.2558. Updating the product as a non-administrative user requires entering administrative credentials into the GUI. Subsequently, these credentials are processed in Teamviewer.exe, which allows any application running in the same non-administrative user context to intercept them in cleartext within process memory. By using this technique, a local attacker is able to obtain administrative credentials in order to elevate privileges. This vulnerability can be exploited by injecting code into Teamviewer.exe which intercepts calls to GetWindowTextW and logs the processed credentials.

TeamViewer 10.x through 13.x allows remote attackers to bypass the brute-force authentication protection mechanism by skipping the "Cancel" step, which makes it easier to determine the correct value of the default 4-digit PIN.

TeamViewer through 13.1.1548 stores a password in Unicode format within TeamViewer.exe process memory between "[00 88] and "[00 00 00]" delimiters, which might make it easier for attackers to obtain sensitive information by leveraging an unattended workstation on which TeamViewer has disconnected but remains running.

Untrusted search path vulnerability in TeamViewer 5.0.8703 and earlier allows local users, and possibly remote attackers, to execute arbitrary code and conduct DLL hijacking attacks via a Trojan horse dwmapi.dll that is located in the same folder as a .tvs or .tvc file.