Midfielder Lampard and full back Cole are out of contract at the end of the campaign and Benitez, appointed last month to replace the sacked Roberto Di Matteo, had said it looked like the end of an era.
However, Benitez said on Sunday he had no idea whether the two England internationals would still be at the club next season.
"When I was asked the other day, maybe it was a misunderstanding or maybe my English was not good enough, but the situation I know is they are finishing their contracts (when the season ends). Past that I do not know," he told the club website.
"I know Frank is happy here and he is a player that is part of the leadership, he is one of the important players, but I do not know about his future.
"So I cannot say yes or no, he will stay or he will leave, in January or even at the end of the season. At this moment I do not know."
Benitez has already come underfire from Chelsea fans upset by the treatment of Di Matteo.
In his three matches in charge the team have managed two 0-0 draws and on Saturday they were beaten 3-1 by West Ham United, leaving them 10 points behind leaders Manchester United.
Benitez said he had met the club's hierarchy to discuss team strengthening in the January transfer window.
"We didn't talk about any players going," the Spaniard added. "The board were asking me about players coming but not about any players leaving."
Lampard is yet to play under Benitez having sustained a calf injury at the end of October.