Cisco IOS XE 3.5E and earlier on WS-C3850, WS-C3860, and AIR-CT5760 devices does not properly parse the "request system shell" challenge response, which allows local users to obtain Linux root access by leveraging administrative privilege, aka Bug ID CSCur09815.
Improper Input Validation The product receives input or data, but it does
not validate or incorrectly validates that the input has the
properties that are required to process the data safely and
correctly.