Privilege Escalation
In plain terms
Gaining higher access rights than originally granted.
Going deeper
Privilege escalation exploits flaws to move from limited access to elevated (admin/root) control, deepening a breach. It turns a foothold into full compromise.
Under the hood
Vertical (to higher rights) or horizontal (to another user); patching and least privilege limit it.
Examples
Exploiting bugs for root, misconfigurations, post-exploitation, lateral movement.
Think of it like...
Like a guest finding a way to get the master key to the whole building.