Polkit: xml policy file with a large number of nested elements may lead to out-of-bounds write

A flaw was found in polkit. When processing an XML policy with 32 or more nested elements in depth, an out-of-bounds write can be triggered. This issue can lead to a crash or other unexpected behavior, and arbitrary code execution is not discarded. To exploit this flaw, a high-privilege account is needed as it's required to place the malicious policy file properly.