The vulnerability centers on missing permission checks in HTTP endpoints. Jenkins plugins typically implement form validation and connection testing through do* methods in Descriptor classes. The security advisory specifically mentions endpoints that should require POST requests and admin permissions, which aligns with common patterns like doTestConnection and doVerifyCredentials. The patch release notes mention fixing CSRF and permission issues, confirming these authentication-related endpoints were vulnerable. The CxDescriptor class is the logical location for these methods based on standard Jenkins plugin architecture.