The AVGUI.exe of AVG/Avast Antivirus before versions before 24.1 can allow a local attacker to escalate privileges via an COM hijack in a time-of-check to time-of-use (TOCTOU) when self protection is disabled.
The product checks the state of a resource before using that resource, but the resource’s state can change between the check and the use in a way that invalidates the results of the check. This can cause the product to perform invalid actions when the resource is in an unexpected state.