diff --git a/backend/src/services/certificate-authority/certificate-authority-dal.ts b/backend/src/services/certificate-authority/certificate-authority-dal.ts
index d5a45ce50..352675441 100644
--- a/backend/src/services/certificate-authority/certificate-authority-dal.ts
+++ b/backend/src/services/certificate-authority/certificate-authority-dal.ts
@@ -218,7 +218,7 @@ export const certificateAuthorityDALFactory = (db: TDbClient) => {
   };
 
   const findWithAssociatedCa = async (
-    filter: Parameters<(typeof caOrm)["find"]>[0] & { dn?: string; type?: string },
+    filter: Parameters<(typeof caOrm)["find"]>[0] & { dn?: string; type?: string; serialNumber?: string },
     { offset, limit, sort = [["createdAt", "desc"]] }: TFindOpt<TCertificateAuthorities> = {},
     tx?: Knex
   ) => {
diff --git a/backend/src/services/certificate-authority/internal/internal-certificate-authority-service.ts b/backend/src/services/certificate-authority/internal/internal-certificate-authority-service.ts
index 6668c806c..80201eab6 100644
--- a/backend/src/services/certificate-authority/internal/internal-certificate-authority-service.ts
+++ b/backend/src/services/certificate-authority/internal/internal-certificate-authority-service.ts
@@ -1068,11 +1068,11 @@ export const internalCertificateAuthorityServiceFactory = ({
       throw new BadRequestError({ message: "Invalid certificate chain" });
 
     const parentCertObj = chainItems[1];
-    const parentCertSubject = parentCertObj.subject;
+    const parentSerialNumber = parentCertObj.serialNumber;
 
     const [parentCa] = await certificateAuthorityDAL.findWithAssociatedCa({
       [`${TableName.CertificateAuthority}.projectId` as "projectId"]: ca.projectId,
-      [`${TableName.InternalCertificateAuthority}.dn` as "dn"]: parentCertSubject
+      [`${TableName.InternalCertificateAuthority}.serialNumber` as "serialNumber"]: parentSerialNumber
     });
 
     const certificateManagerKmsId = await getProjectKmsCertificateKeyId({