The 30-year-old will sign the deal if he comes through a strict medical.
Riggott was released by Middlesbrough at the end of last season.
Cardiff boss Dave Jones said: “Everything’s been agreed on the financial side, we’re just crossing the t’s and dotting the i’s and just making sure.
“Chris had an injury last year that has kept him out for a while, we just want to make sure when we’re bringing players in that they are up to the standard sticking within the fitness regime that we have here.
“Hopefully that will all be concluded over the next few days.”