If malware via monitor cables is a matter of national security, this might be the gadget for you

The UK National Cyber Security Centre has licensed a hardware product called SilentGlass (produced by Goldilock Labs with Sony UK) that inspects and blocks malicious data on HDMI and DisplayPort connections; the article frames the device as a mitigation for niche but plausible risks such as electromagnetic side-channel (TEMPEST/Deep-TEMPEST) attacks and historical EDID/CEC parsing issues, while noting there is no public evidence of widespread real-world exploitation.