The vulnerability stems from email recipient collection logic using SCM changelog data without Jenkins user validation. The Email Extension Plugin's recipient provider implementations (UpstreamComitterRecipientProvider, FailingTestSuspectsRecipientProvider) are primary candidates as they handle dynamic recipient list generation from build/changelog data. These functions would appear in runtime profiles during email list construction when processing SCM changes. The medium confidence reflects inference from vulnerability patterns as no direct patch code was available for analysis.