Heads up, Twitter users: You may want to change your password.

Twitter has announced that it's identified a bug that stored user passwords unmasked in an internal log. The bug has been fixed and Twitter says that there's no evidence of a breach, but it's urging users to change their passwords just to be safe.

"Due to a bug, passwords were written to an internal log before completing the hashing process," says Twitter. "We found this error ourselves, removed the passwords, and are implementing plans to prevent this bug from happening again."

This is a pretty serious issue, even if there's no evidence that a breach occurred. That's especially true when you consider that some people use the same password for multiple services. If you use Twitter, you should definitely change your password to something strong, and change the password if you use that same one on other websites.