A typo on a CV (also commonly called a resume) is not good, although if you notice one after submitting your application, you don’t need to lose all hope!
It is true that hiring managers view such mistakes as careless, and a lack of attention to detail is an unattractive quality in job candidates (especially if you have listed this as one of your skills).
However, we need to keep some healthy perspective and remember that hiring managers and recruiters review hundreds of resumes daily. Hence, they read quickly and might not even notice your mistake.
If your typo is easy to spot, sending an updated CV and explaining that you sent the wrong version before could help. (However, sending the wrong version also signals carelessness, so it is probably best left).
In the future, triple-check your CV for typos and grammatical errors and ask others to proofread it for you before you submit it.