Microphone always enabled in the VM on startup, regardless of the checkbox state in the GUI

[mskov]

This problem must be very old and there are some discussions about it on the VirtualBox forum, e.g. here: ​https://forums.virtualbox.org/viewtopic.php?f=8&t=90066 However I didn't find an existing bug ticket for the issue.

When starting a Linux guest with audio (out) enabled, audio-in gets enabled as well regardless of the state of the "Enable Audio In" checkbox in VirtualBox. And the changes to the state of the checkbox do not have any effect until the microphone is used once inside the guest (which triggers initialization of the audio-in backend in VirtualBox). After the audio-in stream was initialized, one can disable the microphone via the checkbox and re-enable it again.

It does look like a security issue if one can use microphone when the VirtualBox GUI says that "audio in" is disabled.

[DanielH_]

I observe this as well virtualbox-6.1.16 on windows10-1903 host, ubuntu-20.04.1-lts guest.

On VM startup, the windows10 microphone pops in and out of use a few times, and settles on in-use despite VM settings configured audio enabled but no input or output checked; only after flipping a setting while VM running does the windows10 microphone become un-accessed.

(Enabling audio input of course grabs the windows10 microphone, the ONLY time that any attempt to grab the microphone should be done.)

For me, the problem is that the windows10 microphone I have configured is a USB dongle bluetooth headset, and the microphone grab interferes with the headset that can be in use for other purposes (e.g. paired smartphone).

[Mikhail Kovalev]

I cannot reproduce the problem on VirtualBox 6.1.18 any longer. Was there something fixed? I also don't see any changelog entry on the topic.

[Klaus Espenlaub]

Yes, this was fixed in 6.1.18.