[Update: Electronic Arts says its investigation into the matter has come up empty. "We found no indication at this point of a breach of our Origin account database," an EA rep said. "Privacy and security of user account information are of the utmost importance to us. We encourage our players to use Origin user ID and passwords that are unique to their account, and to report any activity they feel may be unauthorized to EA customer support at help.ea.com."
Customers who use the same password across multiple sites may still be at risk as a result of breaches elsewhere, however; in November, the hacker group DerpTrolling claimed to have access to roughly seven million username/password combinations from various services, including 1.7 million Origin accounts.]
Reports of a possible hack of Origin are surfacing on Reddit, where users are reporting unauthorized purchases and other activity on their accounts. The cause and extent of the breach isn't yet clear, but if you have credit card information stored in your account (and really, even if you don't), this would probably be a good time to double-check your purchase history—and change your password.
Some Reddit users say they've been charged for games they didn't buy, while others have received emails reporting failed attempts at purchasing games through their Origin account; one poster said he realized something was up when he started earned achievements for a game he'd never played, while another discovered his account had actually been banned because someone had used it to purchase FIFA and then farm coins.
The good news is that EA customer support appears to be handling the situation well, although obviously some people are having more (or less) luck in that regard than others. Origin also now supports two-factor authorization similar to that of Steam, which when active will send a security code via email or text message whenever the account is logged into from an unrecognized device. Even if you haven't run into any difficulties, I'd strongly recommend turning it on: You'll find it in the "Account and Privacy—Security" section of the Origin drop-down menu.
Electronic Arts said in an email that it is currently investigating the claims. We'll update when we learn more.