"minor update" to the console.
Its focus has been on "system stability" for PS3 software and network services, and it "has been improved." There's no mention of security tweaks.
This really looks to be a small fish update. "A new PS3 system software update, v3.66, will be released soon. With this minor update, system stability during use of PS3 format software and network services has been improved," posted Sony big cheese, Eric Lempel.