diff --git a/x-pack/plugins/cases/server/client/factory.test.ts b/x-pack/plugins/cases/server/client/factory.test.ts
index 69147e888aeec..f73e93afd680c 100644
--- a/x-pack/plugins/cases/server/client/factory.test.ts
+++ b/x-pack/plugins/cases/server/client/factory.test.ts
@@ -52,7 +52,7 @@ describe('CasesClientFactory', () => {
       });
 
       expect(args.securityPluginStart.userProfiles.getCurrent).toHaveBeenCalled();
-      expect(args.securityPluginStart.authc.getCurrentUser).not.toHaveBeenCalled();
+      expect(args.securityServiceStart.authc.getCurrentUser).not.toHaveBeenCalled();
       expect(createCasesClientMocked.mock.calls[0][0].user).toEqual({
         username: 'my_user',
         full_name: 'My user',
@@ -63,7 +63,7 @@ describe('CasesClientFactory', () => {
     it('constructs the user info from the authc service if the user profile is not available', async () => {
       const scopedClusterClient = coreStart.elasticsearch.client.asScoped(request).asCurrentUser;
       // @ts-expect-error: not all fields are needed
-      args.securityPluginStart.authc.getCurrentUser.mockReturnValueOnce({
+      args.securityServiceStart.authc.getCurrentUser.mockReturnValueOnce({
         username: 'my_user_2',
         full_name: 'My user 2',
         email: 'elastic2@elastic.co',
@@ -76,7 +76,7 @@ describe('CasesClientFactory', () => {
       });
 
       expect(args.securityPluginStart.userProfiles.getCurrent).toHaveBeenCalled();
-      expect(args.securityPluginStart.authc.getCurrentUser).toHaveBeenCalled();
+      expect(args.securityServiceStart.authc.getCurrentUser).toHaveBeenCalled();
       expect(createCasesClientMocked.mock.calls[0][0].user).toEqual({
         username: 'my_user_2',
         full_name: 'My user 2',
@@ -95,7 +95,7 @@ describe('CasesClientFactory', () => {
       });
 
       expect(args.securityPluginStart.userProfiles.getCurrent).toHaveBeenCalled();
-      expect(args.securityPluginStart.authc.getCurrentUser).toHaveBeenCalled();
+      expect(args.securityServiceStart.authc.getCurrentUser).toHaveBeenCalled();
       expect(createCasesClientMocked.mock.calls[0][0].user).toEqual({
         username: 'elastic/kibana',
         full_name: null,
@@ -113,7 +113,7 @@ describe('CasesClientFactory', () => {
       });
 
       expect(args.securityPluginStart.userProfiles.getCurrent).toHaveBeenCalled();
-      expect(args.securityPluginStart.authc.getCurrentUser).toHaveBeenCalled();
+      expect(args.securityServiceStart.authc.getCurrentUser).toHaveBeenCalled();
       expect(createCasesClientMocked.mock.calls[0][0].user).toEqual({
         username: null,
         full_name: null,
diff --git a/x-pack/plugins/cases/server/client/factory.ts b/x-pack/plugins/cases/server/client/factory.ts
index 5bb04c1da9e86..865ee2ff3b684 100644
--- a/x-pack/plugins/cases/server/client/factory.ts
+++ b/x-pack/plugins/cases/server/client/factory.ts
@@ -12,6 +12,7 @@ import type {
   ElasticsearchClient,
   SavedObjectsClientContract,
   IBasePath,
+  SecurityServiceStart,
 } from '@kbn/core/server';
 import type { ISavedObjectsSerializer } from '@kbn/core-saved-objects-server';
 import { SECURITY_EXTENSION_ID } from '@kbn/core-saved-objects-server';
@@ -57,6 +58,7 @@ import { EmailNotificationService } from '../services/notifications/email_notifi
 interface CasesClientFactoryArgs {
   securityPluginSetup: SecurityPluginSetup;
   securityPluginStart: SecurityPluginStart;
+  securityServiceStart: SecurityServiceStart;
   spacesPluginStart?: SpacesPluginStart;
   featuresPluginStart: FeaturesPluginStart;
   actionsPluginStart: ActionsPluginStart;
@@ -257,6 +259,7 @@ export class CasesClientFactory {
 
     try {
       const userProfile = await this.options.securityPluginStart.userProfiles.getCurrent({
+        // todo: Access userProfiles from core's UserProfileService contract
         request,
       });
 
@@ -273,7 +276,7 @@ export class CasesClientFactory {
     }
 
     try {
-      const user = this.options.securityPluginStart.authc.getCurrentUser(request);
+      const user = this.options.securityServiceStart.authc.getCurrentUser(request);
 
       if (user != null) {
         return {
diff --git a/x-pack/plugins/cases/server/client/mocks.ts b/x-pack/plugins/cases/server/client/mocks.ts
index 3de350f5a3981..74d3c3de46fa0 100644
--- a/x-pack/plugins/cases/server/client/mocks.ts
+++ b/x-pack/plugins/cases/server/client/mocks.ts
@@ -6,7 +6,11 @@
  */
 
 import type { PublicContract, PublicMethodsOf } from '@kbn/utility-types';
-import { loggingSystemMock, savedObjectsClientMock } from '@kbn/core/server/mocks';
+import {
+  loggingSystemMock,
+  savedObjectsClientMock,
+  securityServiceMock,
+} from '@kbn/core/server/mocks';
 import type { ISavedObjectsSerializer } from '@kbn/core-saved-objects-server';
 
 import {
@@ -226,6 +230,7 @@ export const createCasesClientFactoryMockArgs = () => {
   return {
     securityPluginSetup: securityMock.createSetup(),
     securityPluginStart: securityMock.createStart(),
+    securityServiceStart: securityServiceMock.createStart(),
     spacesPluginStart: spacesMock.createStart(),
     featuresPluginStart: featuresPluginMock.createSetup(),
     actionsPluginStart: actionsMock.createStart(),
diff --git a/x-pack/plugins/cases/server/plugin.ts b/x-pack/plugins/cases/server/plugin.ts
index 2c3f1f10ad254..48ed1722149ed 100644
--- a/x-pack/plugins/cases/server/plugin.ts
+++ b/x-pack/plugins/cases/server/plugin.ts
@@ -186,6 +186,7 @@ export class CasePlugin
       // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
       securityPluginSetup: this.securityPluginSetup!,
       securityPluginStart: plugins.security,
+      securityServiceStart: core.security,
       spacesPluginStart: plugins.spaces,
       featuresPluginStart: plugins.features,
       actionsPluginStart: plugins.actions,
diff --git a/x-pack/plugins/cases/server/services/notifications/email_notification_service.ts b/x-pack/plugins/cases/server/services/notifications/email_notification_service.ts
index e17eb2f22f7bc..22c93f8919a2a 100644
--- a/x-pack/plugins/cases/server/services/notifications/email_notification_service.ts
+++ b/x-pack/plugins/cases/server/services/notifications/email_notification_service.ts
@@ -100,7 +100,7 @@ export class EmailNotificationService implements NotificationService {
       );
 
       const uids = new Set(assignees.map((assignee) => assignee.uid));
-      const userProfiles = await this.security.userProfiles.bulkGet({ uids });
+      const userProfiles = await this.security.userProfiles.bulkGet({ uids }); // todo: access userProfiles from core security service start contract
       const users = userProfiles.map((profile) => profile.user);
 
       const to = users
diff --git a/x-pack/plugins/cases/server/services/user_profiles/index.ts b/x-pack/plugins/cases/server/services/user_profiles/index.ts
index 6a7be7deac4eb..7bc57a96105f5 100644
--- a/x-pack/plugins/cases/server/services/user_profiles/index.ts
+++ b/x-pack/plugins/cases/server/services/user_profiles/index.ts
@@ -27,7 +27,7 @@ const MIN_PROFILES_SIZE = 0;
 
 interface UserProfileOptions {
   securityPluginSetup: SecurityPluginSetup;
-  securityPluginStart: SecurityPluginStart;
+  securityPluginStart: SecurityPluginStart; // TODO: Use core's UserProfileService
   spaces?: SpacesPluginStart;
   licensingPluginStart: LicensingPluginStart;
 }
@@ -58,6 +58,7 @@ export class UserProfileService {
     size?: number;
     owners: string[];
   }) {
+    // TODO: Use core's UserProfileService
     return securityPluginStart.userProfiles.suggest({
       name: searchTerm,
       size,