Norwich defender Francomb and Bennett, from Watford, have agreed one-month deals and will go straight into manager Terry Brown's squad for Saturday's visit of Dagenham in League Two.
Brown moved for the duo after his side leaked 11 goals in their last two matches, while summer signing Curtis Osano is still out injured and skipper Mat Mitchel-King is on compassionate leave.
"I must say a big thank you to the board," Brown told the club's official website.
"With the news that Mat Mitchel-King is not available and Curtis having broken down in training, we were desperate to get a couple of quality players in.
"We haven't got unlimited funds and I am delighted with the quality of the boys we have managed to get in at this late stage before the deadline."