Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
The _checkPolkitPrivilege function in serviceHelper.py in Back In Time (aka backintime) 1.1.18 and earlier uses a deprecated polkit authorization method (unix-process) that is subject to a race condition (time of check, time of use). With this authorization method, the owner of a process requesting a polkit operation is checked by polkitd via /proc/<pid>/status, by which time the requesting process may have been replaced by a different process with the same PID that has different privileges then the original requester.
CWE-362 - Race Condition
A race condition occurs in a shared memory program when two threads/processes access the same shared memory data, and at least one thread executes a write operation. This vulnerability manipulates the time to check vs. time to use (TOC/TOU) gap between the threads in the critical section to cause disorientation in the shared data. The impact can vary from compromising the confidentiality of the system to causing the system to crash or to execute arbitrary code.