CVE-2013-4155: OpenStack Swift allows authenticated users to cause a denial of service

The vulnerability stemmed from improper timestamp validation in DELETE, PUT, and POST handlers. The commit diff shows these methods were modified to add checks against existing timestamps (e.g., comparing orig_timestamp and req_timestamp). Prior to the fix, these functions allowed operations with older timestamps, leading to tombstone proliferation (DELETE) or redundant updates (PUT/POST). The test cases in test_server.py explicitly validate these scenarios, confirming the vulnerable code paths.