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.

References

• https://nvd.nist.gov/vuln/detail/CVE-2020-3979
• https://blog.installbuilder.com/2020/08/updates-and-bug-fixes-with-version-2070.html