Philadelphia-based Comcast said that between Oct. 16 and 19, hackers obtained access to Xfinity usernames and hashed passwords, according to a data breach notice filed with the Office of the Maine Attorney General. In some cases, the last four digits of customers’ social security numbers, contact information, names, dates of birth and security questions were also exposed.

The breach occurred after software provider Citrix announced a vulnerability in a product used by Comcast’s Xfinity cable unit. Citrix issued a software patch to close it.

After Comcast patched the software, however, the cable giant discovered unauthorized access to its internal systems.

[I am no longer an Xfinity customer, but was for almost 20 years while in Minnesota. This sounds pretty sloppy, and somewhat out of character for Xfinity, which impressed me with its stability and technical performance. This sounds massive in nature, so if you are an Xfinity customer, better clean up ASAP by resetting all your passwords and security questions, and use identity-theft protection for a while. — Ed]