Kris Jenner got herself hooked up to a polygraph Thursday night ... and the question that dogged her for years was on the table -- was she involved in the release of Kim's sex tape!
Kris sat next to Kylie as James Corden fired off the question -- "Did you help Kim release her sex tape?" the audience gasped, but Kris assured everyone it was ok, she gave a firm "No" to the question and a dude named John who was manning the machine said she was a truthteller!
So, couple of things ... the sex tape could not be released unless the parties involved gave their signoff ... Kim filed a lawsuit against Vivid Entertainment, which released the tape, but according to Vivid they reached a financial settlement and they dropped the case.
Vivid has long said it would not release a tape without everyone's consent, because in addition to losing the profits it made off the tape, it would be on the hook for invasion of privacy and infliction of emotional distress. Nevertheless, Kim sued and they settled.
Corden didn't follow up with whether she knew if Kim was in on the plot ... something Kim has denied.
BTW ... Corden also asked if Kylie was her favorite child and she gave a resounding "yes" and passed that one too.