[jloughry]

Yes:

Interestingly, the audio chipsets in modern motherboards and sound cards include an option to change the function of an audio port at the software level, a type of audio port programming sometimes referred to as ’jack retasking’. This option is available on most audio chipsets (e.g., Realtek’s audio chipsets) integrated into PC motherboards today. Jack retasking, although documented in the technical specifications, is not well-known [34]. For an in-depth technical discussion on malicious retasking of an audio jack, from the hardware to the operating system level, we refer the interested reader to the following previous work [29].

References:

Mordechai Guri and Yosef Solwicz and Andrey Daidakulov and Yuval Elovici. 'MOSQUITO: Covert Ultrasonic Transmissions between Two Air-Gapped Computers using Speaker-to-Speaker Communication'. arXiv preprint 1803.03422v1 [cs.CR], 9th March 2018.

Mordechai Guri and Yosef Solewicz and Andrey Daidakulov and Yuval Elovici. 'Speake(a)r: Turn speakers to microphones for fun and profit'. 11th USENIX Workshop on Offensive Technologies (WOOT 17). USENIX Association, 2017.

[ocdtrekkie]

Curious how the average user could try to mitigate this threat. Perhaps if you were using speakers connected to an HDMI monitor, rather than an audio jack? Presumably then you'd have to figure out how to exploit both the audio chip on the motherboard and the HDMI device, which I presume would not by default be willing to operate as an input device.