The installUpdates function in yum-cron/yum-cron.py in yum 3.4.3 and earlier does not properly check the return value of the sigCheckPkg function, which allows remote attackers to bypass the RMP package signing restriction via an unsigned package.
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.