At best, the vulnerability could be leveraged by malware and hackers to more easily exploit other security bugs.
Specifically, in terms of the best-case scenario, it is possible the bug could be abused to defeat KASLR: kernel address space layout randomization. This is a defense mechanism used by various operating systems to place components of the kernel in randomized locations in virtual memory. This mechanism can thwart attempts to abuse other bugs within the kernel: typically, exploit code – particularly return-oriented programming exploits – relies on reusing computer instructions in known locations in memory.
This very specifically could mean that you can’t seperate Virtual Machines properly any more.
AMD is quite chuffed to not be affected.