The Italian side had been fined €70,000 (£58,545) and seen their points tally this season reduced by the Disciplinary Commission due to Matteo Gianello’s attempt to fix matches.
The former Partenopei goalkeeper was banned for three years and three months in 2012 after admitting he offered to fix Napoli’s clash with Sampdoria in May 2010.
Cannavaro and Grava were given half-year sentences to sit on the sidelines for not reporting being approached by Gianello ahead of the game, but they insisted that such a conversation never occurred and the defensive veterans have been cleared on appeal.
The Federal Court’s decision means the Azzurri sit just three points behind Juventus in Serie A, level with Lazio but ahead of the Biancocelesti on goal difference.
Cannavaro and Grava will return to Napoli’s squad and will be available for selection immediately.