I am perplexed that we are unable to track down and prosecute who is selling American technology to Putin. Seeing our allies on this list is also disturbing. Some arms merchants are getting rich.
Electronics like webcams, SBC devkits, gyroscopes, GPS transceivers, PID controllers, radios and timers can all be salvaged from America's e-waste. Sanctions controls on them are extraordinarily weak, the hardware itself is all extremely proliferate and low-risk to ship or take cross-border if you desired. The US is not the sole source of any of those components and preventing Russia from getting them would be unlikely to hamstring weapons development or production.
* https://en.wikipedia.org/wiki/Apollo_Guidance_Computer
There's also an interesting series of web pages from a New Zealand man who built his own cruise missile.
1980s era 16 bit and 32 bit tech was enough for a bit of world spanning geodesy, even if tricks had to played to page local features and navigation.
Even a pretty old (relative to 2026) iPhone is a major upgrade to OG cruise missile onboard compute, along with those fancy sensors, cameras and GPS.
A lot of those electronics are so simple and benign that it's nearly impossible to prevent their export. Even the advanced hardware like CUDA SOCs and guidance kits can still get smuggled in by China, who probably has millions of Nvidia Tegra boards collecting dust in storage.