With the default readline key bindings, ALT+B goes back one word, ALT+F goes forward one word.
The default Ubuntu setup additionally provides CTRL+arrows like you’re used to. These are in /etc/inputrc and specified as follows:
# mappings for Ctrl-left-arrow and Ctrl-right-arrow for word moving
"\e[1;5C": forward-word
"\e[1;5D": backward-word
"\e[5C": forward-word
"\e[5D": backward-word
"\e\e[C": forward-word
"\e\e[D": backward-word
Not sure why we need three of them…