Old Microcode

The kernel keeps a table of released microcode. Systems that had microcode older than this at boot will say “Vulnerable”. This means that the system was vulnerable to some known CPU issue. It could be security or functional, the kernel does not know or care.

You should update the CPU microcode to mitigate any exposure. This is usually accomplished by updating the files in /lib/firmware/intel-ucode/ via normal distribution updates. Intel also distributes these files in a github repo:

https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files.git

Just like all the other hardware vulnerabilities, exposure is determined at boot. Runtime microcode updates do not change the status of this vulnerability.