The vulnerability stems from the static assignment of Application.config.secret_token in secret_token.rb, as shown in the pre-patch code. The commit diff explicitly replaces this hard-coded value with dynamic generation logic. While the RPM spec file's postun script placement was incorrect, the root vulnerability manifests in the application's use of a non-unique secret token defined in this initializer file. The CWE-798 classification and patch confirmation further validate this as the vulnerable function.