A new Android 4.3 update has been reported live as early as yesterday. Today, the minor update has been confirmed for several Nexus-line devices, such as the Samsung Galaxy Nexus, the Nexus 4, the 3G version Nexus 7 and the Nexus 10. The update is just 2MB, and targets an unspecified security risk, supposedly.
The new update should bring your Android's Build Number to JWR66Y from JWR66V. If you, like us, haven't got it yet, it shouldn't be long until it pops as if out of thin air.
It's interesting to note that a recent security flaw in Android was found by researches from Symantec, citing a weakness with Android's Java Cryptography Architecture (JCA). Almost immediately thereafter, Android Security Engineer Adrian Ludwig confirmed for Ars Technica that all versions of Android up to 4.2 are susceptible. Of course, whether this new update addresses this remains to be seen, but it does sound plausible.