Apparently, the vulnerability allows hackers to break the 80-bit encryption by cracking two 40-bit keys instead. The new attack has a shorter range than the first, and it takes a bit longer than a couple of seconds, but it's still doable. Model S owners don't have to worry about bad actors using the flaw to break into their cars, though -- all they have to do is upgrade their fobs. Tesla has already fixed the issue, and unlike last year, it doesn't require new hardware. The automaker has started rolling out an over-the-air software update for existing key fobs. In fact, it already implemented the change for all newly manufactured Model S vehicles last month, so new owners don't even have to upgrade.

Wouters was impressed by the way Tesla handled the problem, but he warns that plenty of other cars' key fobs are vulnerable to similar encryption-cracking techniques. Especially since most automakers get their key fobs from third-party manufacturers, and some of them aren't capable of pushing over-the-air updates like Tesla is.

As for Tesla, the automaker seems to be confident that its vehicles are secure enough. A spokesperson pointed out in a statement to Wired that the company introduced a PIN to Drive feature last year that gave owners a way to prevent anybody from driving their vehicles if they can't key in the right PIN.

The spokesperson said: