Automattic and WordPress founder Matt Mullenweg announced today that their servers have been hacked, and source code compromised. Specifically, Automattic had a “low-level (root) break-in” to several servers. He said that “potentially anything on those servers could have been revealed.”

“We have been diligently reviewing logs and records about the break-in to determine the extent of the information exposed, and re-securing avenues used to gain access,” said Mullenweg. “We presume our source code was exposed and copied. While much of our code is Open Source, there are sensitive bits of our and our partners’ code. Beyond that, however, it appears information disclosed was limited.”

The only advice he had for users was to use a secure password. So you might want to consider changing yours.

According to TechCrunch, “site source code includes API keys and Twitter and Facebook passwords which can let interested parties gain access to sensitive information as well as shut people out of their Twitter and Facebook accounts, etc.”

“Our investigation into this matter is ongoing and will take time to complete,” said Mullenweg. “As I said above, we’ve taken comprehensive steps to prevent an incident like this from occurring again.”

Only sites hosted on WordPress.com should be affected (not self-hosted WordPress.org sites).

In related and better news for WordPress and WordPress.com bloggers, Google’s global launch of the Panda update appears to have been good to the domain.