[aric]

Days convey immediacy and scale. "Today" and "same day" balance precision. If time between an exploit becoming known and fixed consistently happened in 100 seconds or less, 0-sec might sound ok. Come to think of it, 0-sec is a fitting pun.

[bentcorner]

"0-sec" isn't too bad, but the plural can make for awkward conversation.

[nostrebored]

0-sec is a terrible name if you're working in sec...