CVE-2022-3457: Origin Validation Error in rdiffweb

The critical vulnerability stems from improper Origin header validation in the set_headers function. The commit diff shows the validation was changed from a prefix check (startswith) to an exact match comparison. The original implementation's use of startswith() allowed malicious origins with matching prefixes (e.g., 'http://victim.com.attacker.net' matching 'http://victim.com'). The added test case 'test_post_with_prefixed_origin' demonstrates this vulnerability by showing prefixed origins were previously accepted. The CWE-346 classification and CVSS 9.8 score confirm the critical nature of this origin validation flaw in the identified function.