InstallBuilder Qt installers built with versions previous to 22.10 try to load DLLs from the installer binary parent directory when displaying popups. This may allow an attacker to plant a malicious DLL in the installer parent directory to allow executing code with the privileges of the installer (when the popup triggers the loading of the library). Exploiting these type of vulnerabilities generally require that an attacker has access to a vulnerable machine to plant the malicious DLL.

On Windows, the uninstaller binary copies itself to a fixed temporary location, which is then executed (the originally called uninstaller exits, so it does not block the installation directory). This temporary location is not randomized and does not restrict access to Administrators only so a potential attacker could plant a binary to replace the copied binary right before it gets called, thus gaining Administrator privileges (if the original uninstaller was executed as Administrator). The vulnerability only affects Windows installers.

Under certain circumstances, when manipulating the Windows registry, InstallBuilder uses the reg.exe system command. The full path to the command is not enforced, which results in a search in the search path until a binary can be identified. This makes the installer/uninstaller vulnerable to Path Interception by Search Order Hijacking, potentially allowing an attacker to plant a malicious reg.exe command so it takes precedence over the system command. The vulnerability only affects Windows installers.

InstallBuilder for Qt Windows (versions prior to 20.7.0) installers look for plugins at a predictable location at initialization time, writable by non-admin users. While those plugins are not required, they are loaded if present, which could allow an attacker to plant a malicious library which could result in code execution with the security scope of the installer.

InstallBuilder AutoUpdate tool and regular installers enabling <checkForUpdates> built with versions earlier than 19.11 are vulnerable to Billion laughs attack (denial-of-service).

Windows binaries generated with InstallBuilder versions earlier than 19.7.0 are vulnerable to tampering even if they contain a valid Authenticode signature.