WEP Wi-Fi security has been known as an easy-to-crack security protocol for a while now, which is why it was superseded by the more secure Wi-Fi Protected Access (WPA) standard. But now a PhD candidate studying encryption has found an exploit in the WPA standard that would allow a hacker to "send bogus data to an unsuspecting WiFi client," completely compromising your Wi-Fi security and opening your network to all sorts of hacking. Lucky for you, it's not terribly difficult to protect yourself against the new exploit.
The key: Just log into your router, switch off Temporal Key Integrity Protocol (TKIP) as an encryption mode, and use Advanced Encryption System (AES) only. TKIP is the only protocol that the hack applies to, so switching to AES-only will ensure that your Wi-Fi network is safe again. It's quick and easy, so do yourself a favour and make the adjustment now so you don't run into any problems in the future.