Vaughan made his first Everton appearance of the season as a 74th-minute substitute during Sunday's 2-2 draw with Liverpool.
He spent the first half of the campaign on loan at Crystal Palace, scoring five goals in his time at Selhurst Park.
Everton's forwards have struggled for goals this season, with midfielder Tim Cahill their top marksman.
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Nigerian international Yakubu has been allowed to join Leicester on loan, leaving manager David Moyes to choose from Louis Saha, Jermaine Beckford, Victor Anichebe, Magaye Gueye and Vaughan in the central striking roles.
Vaughan, who has also had loan spells at Leicester and Derby, made his Toffees debut in April 2005, scoring in a 4-0 win over Crystal Palace.
Cardiff and Hull were linked with a move with the player at the end of last year.
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Source: BBC Sport
Source: BBC Sport