Fix security vulnerability: Equalizer command might allow negative indexes

mentioned in commit e25cc478

mentioned in commit 41c5a018

mentioned in commit 1e31fc2f

mentioned in commit 93f5e649

mentioned in commit ca11e5d6

mentioned in commit f436af62

mentioned in commit f273b59b

mentioned in commit 716d65bc

mentioned in commit 7176e525

mentioned in commit 5855691d