The CISSP contains 100 to 150 multiple-choice and advanced innovative questions.
(ISC)² has introduced Computerized Adaptive Testing (CAT) for all English CISSP exams worldwide. Based on the same exam content outline as the linear, fixed-form exam, CISSP CAT is a more precise and efficient evaluation of your competency. CISSP CAT enables you to prove your knowledge by answering fewer items and completing the exam in half the time.
The (ISC)2 CISSP CAT exam may have 100, up to 150 questions. The test *is* variable length meaning it's dynamically adaptive and you may receive any number of questions between 100 and 150. Obviously 100 is the minimum; if a candidate exhibits high competency levels in advanced questions in each of the 8 domains, the test responds differently with less questions.
I did verify this internally with the person who oversaw the updates to CAT.
Hope this helps!