The body said the suspensions - based on evidence from the McLaren report into state-sponsored doping in Russia - should stand until 31 October.
The six, including Sochi medallists, were named as having had urine samples tampered with at the 2014 Games.
The International Ski Federation (FIS) imposed the original ban in January.
"In the absence of any anti-doping rule violation having been assessed against any of the athletes so far, the temporary suspension shall lapse and the athletes shall be allowed to compete again," Cas said in a statement.
"A further provisional suspension may be imposed on the athletes by the International Ski Federation after that date, and would be subject to appeal."
The decision relates to athletes Alexey Petukhov, Evgenia Shapovalova, Maxim Vylegzhanin, Alexander Legkov, Evgeniy Belov and Julia Ivanova.
Legkov won gold in the men's 50km freestyle at the Winter Olympics in Sochi, with Vylegzhanin taking silver. The pair were also in the men's 4x10km relay team that won silver for Russia, while Vylegzhanin won a further silver in the men's team sprint.
Six Russian cross-country skiers have had their provisional doping bans upheld after a failed appeal to the Court of Arbitration for Sport (Cas).