Board Thread:Metal Gear Solid V/@comment-80.160.74.19-20150930085101/@comment-3116033-20151001091246

Via retcon, is stated in the timeline ad the end of TPP that Solid Snake killed Venom during the Outer Heaven Uprising in 1995 (during the event of MG1), as Venom by that time was the commander-in-chief of Outer Heaven, disguised as Big Boss. So Venom survived to the events of TPP, but not to those of MG.

Less ambiguous than that is impossible.