Meltdown allows attackers to read arbitrary physical memory (including kernel memory) for an unprivileged user process. Meltdown uses out of order instruction execution to leak data via a processor covert channel.
Spectre abuses branch prediction and speculative execution of leak data from via a processor covert channel. Spectre can only read memory from the current process, not the kernel or other physical memory
Refer to the attached PDF for in-depth information on the Impact and Solutions and Workaround.
Authored By - Sathish Damodaran
TCS Cyber Security Practice