What is Notice: Undefined index: in /frmtmp.php on line 134 error and how to solve it?

Question

PHP

This morning I went to the site, and the following errors appeared:
Notice: Undefined index: in /frmtmp.php on line 134
Notice: Undefined variable: kuku in /frmtmp.php on line 149
Notice: Undefined index: in /frmtmp.php on line 118
Notice: Undefined offset: 0 in /frmtmp.php on line 129
Nothing has been updated/changed recently, and there is 0 information on the Internet on this topic. Maybe someone has come across this or can help indicate where to dig.
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Issue resolved, everyone thank!

Answer 1

you're accessing non-existent variables, array indexes...

Answer 2

look here , here and here

Answer 3

Someone's virus broke.
Or a plugin.

Answer 4

You don't have an array declared, there are 3 ways to solve your problem
1. use isset() to check the array.
2. Use @ (Not recommended)
3. Use Try () catch ()
There is also a suggestion at the beginning of the error file to say error_reporting(1); then you won't see the error.