In principle, yes: Leica M has a very short flange distance, so many lenses from systems with longer flange distances can be physically adapted without corrective optics.

However, Canon EF is a very poor match for Leica M in practice. EF lenses are electronically controlled, so without a specialized active adapter you generally won’t have aperture control, and focusing may also be impractical. On a Leica M body, even if the lens can be mounted, you’re unlikely to get a usable setup for normal focusing and operation.

So the short answer is: physically possible in theory, but functionally not a good combination. The key limitation is not just mount spacing, but the lack of mechanical aperture control and the mismatch with how Leica M bodies are designed to focus lenses.