Sudo: The "no new privileges" flag is set, which prevents sudo from running as root

sudo apt update
sudo: The "no new privileges" flag is set, which prevents sudo from running as root.
sudo: If sudo is running in a container, you may need to adjust the container configuration to disable the flag.

suddenly this happening. I did some modifications but cant remember which file. please need assistance.

You are not giving us much to work with here... Based on your username and the fact that you asked another question related to coding, I'm going to suggest reading through this:

For future reference, it's a good idea to make snapshots of your system with tools such as Timeshift. This way, if something goes wrong after fiddling with your system, you can revert back to a previous snapshot.

as a temporary workaround, try this in the terminal:

su -su

Then type your usual sudo password and you will be running commands as root, making unnecessary to add "sudo" at the beginning of each command

So if you just want to update packages, now you would type

apt update

Including the word "sudo" is unnecessary, but it won't break anything if you accidentally do

Only use this workaround when running commands that strictly would require "sudo", as some programs will refuse to launch under the root account (and overall it's easier to break things when constantly running as root). If you are done running the command that requires sudo and want to run a command that doesn't require it, type "exit" to go back to running commands as the user account