If you mean browser privilege escalation, it usually refers to a bug or attack that lets code escape the browser’s intended security boundaries and gain more powerful access than normal web content should have. Common routes include browser engine bugs, extension issues, UI/permission bypasses, sandbox escapes, and cross-site scripting that is chained into higher privileges. mozilla

Common browser paths

• Extension privilege escalation. Malicious pages or messages exploit weak extension messaging, storage, or permission handling to read data or invoke privileged APIs. sentinelone
• Browser engine / sandbox escape. A rendering or JavaScript engine bug can let attacker-controlled code run with browser-level or system-level privileges. mozilla
• UI or zone bypasses. Tricks around popup blockers, user gestures, or browser trust zones can lead to code executing with elevated trust. mozilla

What defenders do

• Keep browsers and extensions fully patched.
• Minimize extension permissions and remove unused add-ons.
• Use browser isolation or hardened profiles for high-risk browsing.
• Treat unusual UI-gated actions as suspicious and block them in policy where possible. sentinelone

If you want, I can also narrow this to Chrome extension privilege escalation, browser sandbox escapes, or defensive testing steps.