Kernel read/write is a high-impact exploit primitive that lets an attacker directly read from and write to kernel memory. The kernel runs at the most privileged level of an operating system, so control over its memory can expose secrets, alter security decisions, and change how processes, files, or drivers behave.
Security teams treat this primitive as a major milestone because it often marks the jump from a limited bug to full system compromise. In real exploit chains, an attacker may first gain code execution in a browser or app, then combine that foothold with a kernel vulnerability such as a use-after-free or race condition to obtain kernel read/write. Defenders look for this pattern because once an attacker can read kernel memory, they may bypass address randomization or locate important objects; once they can write, they may patch credentials, disable checks, or prepare further privilege escalation. Preventing it usually depends on strong memory-safety fixes, kernel hardening, and rapid patching.