diff --git a/README.md b/README.md
index cbb7730da3..613eeb89e8 100644
--- a/README.md
+++ b/README.md
@@ -283,3 +283,70 @@ $ docker compose run --rm init-core
 > This `init-core-fca-low` container is a dependency of the `core-fca-low` container.  
 > It will run the migration script every time the `core-fca-low` container is started.  
 > No need to do it manually when using the `dks switch`
+
+
+## Generate a new version of class-validator-0.14.2
+
+We forked the class-validator package because we needed inhertiance features and is not yet merged [into the main branch](https://github.com/typestack/class-validator/pull/2641).
+
+To update the package, follow these steps.
+
+Get and update the project:
+```bash
+git clone git@github.com:proconnect-gouv/class-validator.git
+```
+
+Update the version attribute of `class-validator/package.json`:
+```json
+{
+  "name": "class-validator",
+  "version": "0.14.2-proconnect.1",
+  "...": "..."
+}
+```
+
+Build the new package:
+```bash
+rm -rf build
+npm ci --ignore-scripts
+npm run prettier:check
+npm run lint:check
+npm run test:ci
+npm run build:es2015
+npm run build:esm5
+npm run build:cjs
+npm run build:umd
+npm run build:types
+cp LICENSE build/LICENSE
+cp README.md build/README.md
+jq 'del(.devDependencies) | del(.scripts)' package.json > build/package.json
+npm pack ./build
+```
+
+Then push the built package in a dedicated branch:
+```bash
+git checkout -b build-0.14.2-proconnect.1
+find . -mindepth 1 -maxdepth 1 \
+  ! -name '.git' \
+  ! -name '.idea' \
+  ! -name '.gitignore' \
+  ! -name 'build' \
+  -exec rm -rf {} +
+mv build/* .
+rmdir build
+git add .
+git commit -m "Build version 0.14.2-proconnect.1"
+git push
+```
+
+Update `federation/back/package.json`:
+
+```json
+{
+  "dependencies": {
+    "class-validator": "git+https://github.com/proconnect-gouv/class-validator.git#build-0.14.2-proconnect.1",
+  }
+}
+```
+
+Run yarn install.
diff --git a/back/apps/core-fca-low/src/controllers/interaction.controller.spec.ts b/back/apps/core-fca-low/src/controllers/interaction.controller.spec.ts
index ee95321a21..e60ff2014d 100644
--- a/back/apps/core-fca-low/src/controllers/interaction.controller.spec.ts
+++ b/back/apps/core-fca-low/src/controllers/interaction.controller.spec.ts
@@ -16,7 +16,7 @@ import { ISessionService, SessionService } from '@fc/session';
 import { getLoggerMock } from '@mocks/logger';
 
 // --- Mocks for external dependencies ---
-import { UserSession } from '../dto';
+import { GetVerifySessionDto, UserSession } from '../dto';
 import { CoreFcaAgentNotFromPublicServiceException } from '../exceptions';
 import { CoreFcaControllerService } from '../services';
 import { InteractionController } from './interaction.controller';
@@ -380,7 +380,7 @@ describe('InteractionController', () => {
           idpIdentity: { sub: 'user1', extraClaims: 'extra' },
         }),
         set: jest.fn(),
-      } as unknown as ISessionService<UserSession>;
+      } as unknown as ISessionService<GetVerifySessionDto>;
       const interactionAcr = 'high';
 
       identityProviderMock.isActiveById.mockResolvedValue(true);
@@ -422,7 +422,7 @@ describe('InteractionController', () => {
           isSilentAuthentication: true,
           idpId: 'idp123',
         }),
-      } as unknown as ISessionService<UserSession>;
+      } as unknown as ISessionService<GetVerifySessionDto>;
 
       identityProviderMock.isActiveById.mockResolvedValue(false);
 
@@ -440,7 +440,7 @@ describe('InteractionController', () => {
           interactionId: 'interaction123',
           idpId: 'idp123',
         }),
-      } as unknown as ISessionService<UserSession>;
+      } as unknown as ISessionService<GetVerifySessionDto>;
 
       identityProviderMock.isActiveById.mockResolvedValue(false);
       configServiceMock.get.mockReturnValueOnce({ urlPrefix: '/prefix' });
@@ -461,7 +461,7 @@ describe('InteractionController', () => {
           idpId: 'idp123',
           idpIdentity: { is_service_public: false },
         }),
-      } as unknown as ISessionService<UserSession>;
+      } as unknown as ISessionService<GetVerifySessionDto>;
 
       identityProviderMock.isActiveById.mockResolvedValue(true);
       serviceProviderMock.getById.mockResolvedValue({ type: 'public' });
@@ -479,7 +479,7 @@ describe('InteractionController', () => {
           spEssentialAcr: 'high',
           idpAcr: 'low',
         }),
-      } as unknown as ISessionService<UserSession>;
+      } as unknown as ISessionService<GetVerifySessionDto>;
 
       identityProviderMock.isActiveById.mockResolvedValue(true);
       serviceProviderMock.getById.mockResolvedValue({ type: 'public' });
diff --git a/back/apps/core-fca-low/src/controllers/interaction.controller.ts b/back/apps/core-fca-low/src/controllers/interaction.controller.ts
index d474cb59cd..aa5fad1175 100644
--- a/back/apps/core-fca-low/src/controllers/interaction.controller.ts
+++ b/back/apps/core-fca-low/src/controllers/interaction.controller.ts
@@ -211,7 +211,7 @@ export class InteractionController {
     @Res() res: Response,
     @Param() _params: Interaction,
     @UserSessionDecorator(GetVerifySessionDto)
-    userSessionService: ISessionService<UserSession>,
+    userSessionService: ISessionService<GetVerifySessionDto>,
   ) {
     const {
       amr,
diff --git a/back/apps/core-fca-low/src/controllers/oidc-client.controller.spec.ts b/back/apps/core-fca-low/src/controllers/oidc-client.controller.spec.ts
index 3873844398..eb0d99b565 100644
--- a/back/apps/core-fca-low/src/controllers/oidc-client.controller.spec.ts
+++ b/back/apps/core-fca-low/src/controllers/oidc-client.controller.spec.ts
@@ -5,7 +5,7 @@ import { Test, TestingModule } from '@nestjs/testing';
 import { AccountFcaService } from '@fc/account-fca';
 import { validateDto } from '@fc/common';
 import { ConfigService } from '@fc/config';
-import { UserSession } from '@fc/core';
+import { GetIdentityProviderSelectionSessionDto, UserSession } from '@fc/core';
 import { CryptographyService } from '@fc/cryptography';
 import { CsrfService } from '@fc/csrf';
 import { LoggerService } from '@fc/logger';
@@ -128,7 +128,7 @@ describe('OidcClientController', () => {
       const email = 'user@example.com';
       const userSession = {
         get: jest.fn().mockReturnValue({ idpLoginHint: email }),
-      } as unknown as ISessionService<UserSession>;
+      } as unknown as ISessionService<GetIdentityProviderSelectionSessionDto>;
 
       const providers = [
         { title: 'Provider One', uid: 'idp1' },
diff --git a/back/apps/core-fca-low/src/controllers/oidc-client.controller.ts b/back/apps/core-fca-low/src/controllers/oidc-client.controller.ts
index c20c9cfd6d..5a5c839359 100644
--- a/back/apps/core-fca-low/src/controllers/oidc-client.controller.ts
+++ b/back/apps/core-fca-low/src/controllers/oidc-client.controller.ts
@@ -68,7 +68,7 @@ export class OidcClientController {
   async getIdentityProviderSelection(
     @Res() res: Response,
     @UserSessionDecorator(GetIdentityProviderSelectionSessionDto)
-    userSession: ISessionService<UserSession>,
+    userSession: ISessionService<GetIdentityProviderSelectionSessionDto>,
   ) {
     const { idpLoginHint: email } = userSession.get();
 
@@ -201,7 +201,7 @@ export class OidcClientController {
      * @ticket FC-1020
      */
     @UserSessionDecorator(GetOidcCallbackSessionDto)
-    userSession: ISessionService<UserSession>,
+    userSession: ISessionService<GetOidcCallbackSessionDto>,
   ) {
     // The session is duplicated here to mitigate cookie-theft-based attacks.
     // For more information, refer to: https://gitlab.dev-franceconnect.fr/france-connect/fc/-/issues/1288
diff --git a/back/apps/core-fca-low/src/decorators/user-session.decorator.spec.ts b/back/apps/core-fca-low/src/decorators/user-session.decorator.spec.ts
index 3d8d86408f..2233ae42f9 100644
--- a/back/apps/core-fca-low/src/decorators/user-session.decorator.spec.ts
+++ b/back/apps/core-fca-low/src/decorators/user-session.decorator.spec.ts
@@ -63,45 +63,25 @@ describe('UserSessionDecoratorFactory', () => {
     jest.restoreAllMocks();
   });
 
-  it('should return the bound session service with all methods when validations pass (with mandatory DTO)', async () => {
+  it('should return the bound session service with all methods when validations pass', async () => {
     // Define a dummy DTO for mandatory validation.
     class DummyDto {}
 
-    // Simulate no validation errors for both the mandatory DTO and the UserSession.
     const validateMock = jest.mocked(validate);
-    validateMock.mockResolvedValueOnce([]); // For validating DummyDto instance.
-    validateMock.mockResolvedValueOnce([]); // For validating UserSession instance.
+    validateMock.mockResolvedValueOnce([]);
 
     const result = await UserSessionDecoratorFactory(
       DummyDto,
       fakeExecutionContext,
     );
 
-    // Expect the bound session service to have all expected methods.
-    expect(typeof result.get).toBe('function');
-    expect(typeof result.set).toBe('function');
-    expect(typeof result.commit).toBe('function');
-    expect(typeof result.duplicate).toBe('function');
-    expect(typeof result.reset).toBe('function');
-    expect(typeof result.destroy).toBe('function');
-
     // Call duplicate and ensure that it calls the underlying sessionService.duplicate with the response.
     const duplicateResult = result.duplicate();
     expect(fakeSessionService.duplicate).toHaveBeenCalledWith(fakeResponse);
     expect(duplicateResult).toBe('duplicatedSession');
-
-    // Call reset and destroy to verify they are bound with the response.
-    await result.reset();
-    expect(fakeSessionService.reset).toHaveBeenCalledWith(fakeResponse);
-    await result.destroy();
-    expect(fakeSessionService.destroy).toHaveBeenCalledWith(fakeResponse);
-
-    // Commit is not bound with the response so just check it is called.
-    await result.commit();
-    expect(fakeSessionService.commit).toHaveBeenCalled();
   });
 
-  it('should throw SessionInvalidSessionException if mandatory DTO validation fails', async () => {
+  it('should throw SessionInvalidSessionException if a session DTO validation fails', async () => {
     class DummyDto {}
     const validationError = [
       {
@@ -110,9 +90,8 @@ describe('UserSessionDecoratorFactory', () => {
       },
     ];
 
-    // Simulate a validation error for the mandatory DTO.
     const validateMock = jest.mocked(validate);
-    validateMock.mockResolvedValueOnce(validationError); // First call (for DummyDto)
+    validateMock.mockResolvedValueOnce(validationError);
 
     await expect(
       UserSessionDecoratorFactory(DummyDto, fakeExecutionContext),
@@ -121,28 +100,9 @@ describe('UserSessionDecoratorFactory', () => {
     expect(validateMock).toHaveBeenCalledTimes(1);
   });
 
-  it('should throw SessionInvalidSessionException if UserSession validation fails', async () => {
-    class DummyDto {}
-    const validationError = [
-      { property: 'user', constraints: { isDefined: 'user must be defined' } },
-    ];
-
-    // Simulate successful validation for the mandatory DTO, then a failure for the UserSession.
-    const validateMock = jest.mocked(validate);
-    validateMock.mockResolvedValueOnce([]); // For DummyDto
-    validateMock.mockResolvedValueOnce(validationError); // For UserSession
-
-    await expect(
-      UserSessionDecoratorFactory(DummyDto, fakeExecutionContext),
-    ).rejects.toThrowError(SessionInvalidSessionException);
-
-    expect(validateMock).toHaveBeenCalledTimes(2);
-  });
-
-  it('should validate only UserSession when no mandatory DTO is provided', async () => {
-    // When no mandatory DTO is provided, only one validation (for UserSession) occurs.
+  it('should validate only UserSession when no session DTO is provided', async () => {
     const validateMock = jest.mocked(validate);
-    validateMock.mockResolvedValueOnce([]); // For UserSession
+    validateMock.mockResolvedValueOnce([]);
 
     const result = await UserSessionDecoratorFactory(
       undefined,
@@ -152,14 +112,13 @@ describe('UserSessionDecoratorFactory', () => {
     expect(typeof result.get).toBe('function');
   });
 
-  it('should throw SessionInvalidSessionException if UserSession validation fails when no mandatory DTO is provided', async () => {
+  it('should throw SessionInvalidSessionException if UserSession validation fails when no session DTO is provided', async () => {
     const validationError = [
       { property: 'user', constraints: { isDefined: 'user must be defined' } },
     ];
 
-    // Simulate a validation error for UserSession when no mandatory DTO is provided.
     const validateMock = jest.mocked(validate);
-    validateMock.mockResolvedValueOnce(validationError); // For UserSession
+    validateMock.mockResolvedValueOnce(validationError);
 
     await expect(
       UserSessionDecoratorFactory(undefined, fakeExecutionContext),
diff --git a/back/apps/core-fca-low/src/decorators/user-session.decorator.ts b/back/apps/core-fca-low/src/decorators/user-session.decorator.ts
index db766c888a..c6adebb7ff 100644
--- a/back/apps/core-fca-low/src/decorators/user-session.decorator.ts
+++ b/back/apps/core-fca-low/src/decorators/user-session.decorator.ts
@@ -14,7 +14,7 @@ import { ISessionService } from '@fc/session/interfaces';
 import { SessionService } from '@fc/session/services';
 
 export const UserSessionDecoratorFactory = async (
-  mandatoryPropertiesDto: Class<unknown>,
+  userSessionDto: Class<UserSession> = UserSession,
   ctx: ExecutionContext,
 ): Promise<ISessionService<UserSession>> => {
   const sessionService =
@@ -40,22 +40,17 @@ export const UserSessionDecoratorFactory = async (
 
   const sessionData = boundSessionService.get();
 
-  if (mandatoryPropertiesDto) {
-    const object = plainToInstance(mandatoryPropertiesDto, sessionData);
-    const mandatoryPropertiesErrors = await validate(object as object);
+  const object = plainToInstance(userSessionDto, sessionData);
+  const validationErrors = await validate(object as object);
 
-    if (mandatoryPropertiesErrors.length) {
+  if (validationErrors.length) {
+    if (userSessionDto === UserSession) {
+      throw new SessionInvalidSessionException();
+    } else {
       throw new SessionInvalidMandatoryFieldsException();
     }
   }
 
-  const object = plainToInstance(UserSession, sessionData);
-  const typeErrors = await validate(object as object);
-
-  if (typeErrors.length) {
-    throw new SessionInvalidSessionException();
-  }
-
   return boundSessionService;
 };
 
diff --git a/back/apps/core-fca-low/src/dto/base-identity.dto.ts b/back/apps/core-fca-low/src/dto/base-identity.dto.ts
deleted file mode 100644
index 1833b7fbcf..0000000000
--- a/back/apps/core-fca-low/src/dto/base-identity.dto.ts
+++ /dev/null
@@ -1,72 +0,0 @@
-import {
-  IsAscii,
-  IsBoolean,
-  IsEmail,
-  IsOptional,
-  IsString,
-  MaxLength,
-  MinLength,
-} from 'class-validator';
-
-export abstract class BaseIdentityDto {
-  @MinLength(1)
-  @MaxLength(256)
-  @IsAscii()
-  sub: string;
-
-  @IsString()
-  @MinLength(1)
-  @MaxLength(256)
-  given_name: string;
-
-  @IsString()
-  @MinLength(1)
-  @MaxLength(256)
-  usual_name: string;
-
-  @IsEmail()
-  email: string;
-
-  @MinLength(1)
-  @MaxLength(256)
-  @IsAscii()
-  uid: string;
-
-  @IsString()
-  @MinLength(1)
-  @MaxLength(256)
-  @IsOptional()
-  siren?: string;
-
-  @IsString()
-  @MaxLength(256)
-  siret?: string;
-
-  @IsString()
-  @MinLength(1)
-  @MaxLength(256)
-  @IsOptional()
-  organizational_unit?: string;
-
-  @IsString()
-  @MinLength(1)
-  @MaxLength(256)
-  @IsOptional()
-  belonging_population?: string;
-
-  @IsString()
-  @MinLength(1)
-  @MaxLength(256)
-  @IsOptional()
-  'chorusdt:societe'?: string;
-
-  @IsString()
-  @MinLength(1)
-  @MaxLength(256)
-  @IsOptional()
-  'chorusdt:matricule'?: string;
-
-  @IsBoolean()
-  @IsOptional()
-  is_service_public?: boolean;
-}
diff --git a/back/apps/core-fca-low/src/dto/get-identity-provider-selection-session-dto.ts b/back/apps/core-fca-low/src/dto/get-identity-provider-selection-session-dto.ts
index bf7255aec3..ff1d9aa432 100644
--- a/back/apps/core-fca-low/src/dto/get-identity-provider-selection-session-dto.ts
+++ b/back/apps/core-fca-low/src/dto/get-identity-provider-selection-session-dto.ts
@@ -1,6 +1,8 @@
 import { IsDefined } from 'class-validator';
 
-export class GetIdentityProviderSelectionSessionDto {
+import { UserSession } from '@fc/core/dto/user-session.dto';
+
+export class GetIdentityProviderSelectionSessionDto extends UserSession {
   @IsDefined()
-  readonly idpLoginHint: string;
+  declare idpLoginHint: string;
 }
diff --git a/back/apps/core-fca-low/src/dto/get-oidc-callback-session-dto.ts b/back/apps/core-fca-low/src/dto/get-oidc-callback-session-dto.ts
index f33b4655f6..12075b2209 100644
--- a/back/apps/core-fca-low/src/dto/get-oidc-callback-session-dto.ts
+++ b/back/apps/core-fca-low/src/dto/get-oidc-callback-session-dto.ts
@@ -1,18 +1,20 @@
 import { IsDefined } from 'class-validator';
 
-export class GetOidcCallbackSessionDto {
+import { UserSession } from '@fc/core/dto/user-session.dto';
+
+export class GetOidcCallbackSessionDto extends UserSession {
   @IsDefined()
-  readonly idpId: string;
+  declare idpId: string;
 
   @IsDefined()
-  readonly idpName: string;
+  declare idpName: string;
 
   @IsDefined()
-  readonly idpLabel: string;
+  declare idpLabel: string;
 
   @IsDefined()
-  readonly idpState: string;
+  declare idpState: string;
 
   @IsDefined()
-  readonly idpNonce: string;
+  declare idpNonce: string;
 }
diff --git a/back/apps/core-fca-low/src/dto/get-verify-session-dto.ts b/back/apps/core-fca-low/src/dto/get-verify-session-dto.ts
index c2de186ce1..e0493beaac 100644
--- a/back/apps/core-fca-low/src/dto/get-verify-session-dto.ts
+++ b/back/apps/core-fca-low/src/dto/get-verify-session-dto.ts
@@ -1,17 +1,21 @@
-import { IsDefined } from 'class-validator';
+import { Type } from 'class-transformer';
+import { IsDefined, ValidateNested } from 'class-validator';
 
 import { IdentityFromIdpDto } from './identity-from-idp.dto';
+import { UserSession } from './user-session.dto';
 
-export class GetVerifySessionDto {
+export class GetVerifySessionDto extends UserSession {
   @IsDefined()
-  readonly idpId: string;
+  declare idpId: string;
 
   @IsDefined()
-  readonly idpName: string;
+  declare idpName: string;
 
   @IsDefined()
-  readonly idpLabel: string;
+  declare idpLabel: string;
 
   @IsDefined()
-  readonly idpIdentity: Partial<IdentityFromIdpDto>;
+  @ValidateNested()
+  @Type(() => IdentityFromIdpDto)
+  declare idpIdentity: IdentityFromIdpDto;
 }
diff --git a/back/apps/core-fca-low/src/dto/identity-for-sp.dto.ts b/back/apps/core-fca-low/src/dto/identity-for-sp.dto.ts
index c7868c11f1..5ef3d1b1a3 100644
--- a/back/apps/core-fca-low/src/dto/identity-for-sp.dto.ts
+++ b/back/apps/core-fca-low/src/dto/identity-for-sp.dto.ts
@@ -1,22 +1,21 @@
 import {
+  IsDefined,
   IsObject,
-  IsOptional,
   IsString,
   MaxLength,
   MinLength,
 } from 'class-validator';
 
-import { BaseIdentityDto } from '@fc/core/dto/base-identity.dto';
-
 import { IsPhoneNumberSimpleValidator } from '../validators/is-phone-number-simple-validator.validator';
 import { IsSiret } from '../validators/is-siret-validator';
+import { IdentityFromIdpDto } from './identity-from-idp.dto';
 
-export class IdentityForSpDto extends BaseIdentityDto {
+export class IdentityForSpDto extends IdentityFromIdpDto {
+  @IsDefined({ groups: ['siret'] })
   @MinLength(1, { groups: ['siret'] })
   @IsSiret({ groups: ['siret'] })
   declare siret: string;
 
-  @IsOptional({ groups: ['phone_number'] })
   @IsString({ groups: ['phone_number'] })
   @MinLength(1, { groups: ['phone_number'] })
   @MaxLength(256, { groups: ['phone_number'] })
diff --git a/back/apps/core-fca-low/src/dto/identity-from-idp.dto.ts b/back/apps/core-fca-low/src/dto/identity-from-idp.dto.ts
index 0c78063eaa..d4e6bdca8f 100644
--- a/back/apps/core-fca-low/src/dto/identity-from-idp.dto.ts
+++ b/back/apps/core-fca-low/src/dto/identity-from-idp.dto.ts
@@ -1,15 +1,80 @@
 import { Transform } from 'class-transformer';
-import { IsOptional } from 'class-validator';
+import {
+  IsAscii,
+  IsBoolean,
+  IsEmail,
+  IsOptional,
+  IsString,
+  MaxLength,
+  MinLength,
+} from 'class-validator';
 import { isString } from 'lodash';
 
-import { BaseIdentityDto } from '@fc/core/dto/base-identity.dto';
+export class IdentityFromIdpDto {
+  @MinLength(1)
+  @MaxLength(256)
+  @IsAscii()
+  sub: string;
 
-export class IdentityFromIdpDto extends BaseIdentityDto {
+  @IsString()
+  @MinLength(1)
+  @MaxLength(256)
+  given_name: string;
+
+  @IsString()
+  @MinLength(1)
+  @MaxLength(256)
+  usual_name: string;
+
+  @IsEmail()
+  email: string;
+
+  @MinLength(1)
+  @MaxLength(256)
+  @IsAscii()
+  uid: string;
+
+  @IsString()
+  @MinLength(1)
+  @MaxLength(256)
+  @IsOptional()
+  siren?: string;
+
+  @IsString()
+  @MaxLength(256)
   @IsOptional()
   @Transform(({ value }) =>
     isString(value) ? value.replace(/\s/g, '') : value,
   )
-  declare siret?: string;
+  siret?: string;
+
+  @IsString()
+  @MinLength(1)
+  @MaxLength(256)
+  @IsOptional()
+  organizational_unit?: string;
+
+  @IsString()
+  @MinLength(1)
+  @MaxLength(256)
+  @IsOptional()
+  belonging_population?: string;
+
+  @IsString()
+  @MinLength(1)
+  @MaxLength(256)
+  @IsOptional()
+  'chorusdt:societe'?: string;
+
+  @IsString()
+  @MinLength(1)
+  @MaxLength(256)
+  @IsOptional()
+  'chorusdt:matricule'?: string;
+
+  @IsBoolean()
+  @IsOptional()
+  is_service_public?: boolean;
 
   @IsOptional()
   phone_number?: any;
diff --git a/back/apps/core-fca-low/src/dto/index.ts b/back/apps/core-fca-low/src/dto/index.ts
index 091d8d498a..5ded411767 100644
--- a/back/apps/core-fca-low/src/dto/index.ts
+++ b/back/apps/core-fca-low/src/dto/index.ts
@@ -1,6 +1,5 @@
 export * from './active-user-session.dto';
 export * from './app-config.dto';
-export * from './base-identity.dto';
 export * from './core-fca-config.dto';
 export * from './core-fca-session.dto';
 export * from './get-identity-provider-selection-session-dto';
diff --git a/back/apps/core-fca-low/src/dto/user-session.dto.ts b/back/apps/core-fca-low/src/dto/user-session.dto.ts
index ab38117e14..9f9bb304cb 100644
--- a/back/apps/core-fca-low/src/dto/user-session.dto.ts
+++ b/back/apps/core-fca-low/src/dto/user-session.dto.ts
@@ -92,7 +92,7 @@ export class UserSession {
   @IsString()
   @IsNotEmpty()
   @Expose()
-  readonly idpId?: string;
+  idpId?: string;
 
   @IsOptional()
   @IsString()
diff --git a/back/apps/core-fca-low/src/services/identity.sanitizer.ts b/back/apps/core-fca-low/src/services/identity.sanitizer.ts
index 676a445c0a..fe279f3834 100644
--- a/back/apps/core-fca-low/src/services/identity.sanitizer.ts
+++ b/back/apps/core-fca-low/src/services/identity.sanitizer.ts
@@ -97,7 +97,6 @@ export class IdentitySanitizer {
     const identityValidationErrors = await validate(identityForSp);
     // But we may yet throw if the IdP has no default value
     // to substitute for an incorrect siret
-    /* istanbul ignore next */
     await this.throwIfInvalid(
       identityValidationErrors,
       idpId,
diff --git a/back/package.json b/back/package.json
index 785b9c6048..8b3f77723c 100644
--- a/back/package.json
+++ b/back/package.json
@@ -49,7 +49,7 @@
     "axios": "^1.12.0",
     "body-parser": "^2.2.0",
     "class-transformer": "^0.5.1",
-    "class-validator": "^0.14.2",
+    "class-validator": "proconnect-gouv/class-validator#build-0.14.2-proconnect.1",
     "cookie-parser": "^1.4.7",
     "deep-freeze": "^0.0.1",
     "ejs": "^3.1.10",
diff --git a/back/yarn.lock b/back/yarn.lock
index bcf3140ba8..a109860a95 100644
--- a/back/yarn.lock
+++ b/back/yarn.lock
@@ -2426,10 +2426,9 @@ class-transformer@^0.5.1:
   resolved "https://registry.npmjs.org/class-transformer/-/class-transformer-0.5.1.tgz"
   integrity sha512-SQa1Ws6hUbfC98vKGxZH3KFY0Y1lm5Zm0SY8XX9zbK7FJCyVEac3ATW0RIpwzW+oOfmHE5PMPufDG9hCfoEOMw==
 
-class-validator@^0.14.2:
-  version "0.14.2"
-  resolved "https://registry.yarnpkg.com/class-validator/-/class-validator-0.14.2.tgz#a3de95edd26b703e89c151a2023d3c115030340d"
-  integrity sha512-3kMVRF2io8N8pY1IFIXlho9r8IPUUIfHe2hYVtiebvAzU2XeQFXTv+XI4WX+TnXmtwXMDcjngcpkiPM0O9PvLw==
+class-validator@proconnect-gouv/class-validator#build-0.14.2-proconnect.1:
+  version "0.14.2-proconnect.1"
+  resolved "https://codeload.github.com/proconnect-gouv/class-validator/tar.gz/2c1e9983782a509917df586298333f55982fcaf0"
   dependencies:
     "@types/validator" "^13.11.8"
     libphonenumber-js "^1.11.1"
@@ -6685,7 +6684,14 @@ string_decoder@^1.1.1:
   dependencies:
     safe-buffer "~5.2.0"
 
-"strip-ansi-cjs@npm:strip-ansi@^6.0.1", strip-ansi@^6.0.0, strip-ansi@^6.0.1:
+"strip-ansi-cjs@npm:strip-ansi@^6.0.1":
+  version "6.0.1"
+  resolved "https://registry.npmjs.org/strip-ansi/-/strip-ansi-6.0.1.tgz"
+  integrity sha512-Y38VPSHcqkFrCpFnQ9vuSXmquuv5oXOKpGeT6aGrr3o3Gc9AlVa6JBfUSOCnbxGGZF+/0ooI7KrPuUSztUdU5A==
+  dependencies:
+    ansi-regex "^5.0.1"
+
+strip-ansi@^6.0.0, strip-ansi@^6.0.1:
   version "6.0.1"
   resolved "https://registry.npmjs.org/strip-ansi/-/strip-ansi-6.0.1.tgz"
   integrity sha512-Y38VPSHcqkFrCpFnQ9vuSXmquuv5oXOKpGeT6aGrr3o3Gc9AlVa6JBfUSOCnbxGGZF+/0ooI7KrPuUSztUdU5A==
@@ -7329,7 +7335,7 @@ word-wrap@^1.2.5:
   resolved "https://registry.npmjs.org/word-wrap/-/word-wrap-1.2.5.tgz"
   integrity sha512-BN22B5eaMMI9UMtjrGd5g5eCYPpCPDUy0FJXbYsaT5zYxjFOckS53SQDE3pWkVoWpHXVb3BrYcEN4Twa55B5cA==
 
-"wrap-ansi-cjs@npm:wrap-ansi@^7.0.0", wrap-ansi@^7.0.0:
+"wrap-ansi-cjs@npm:wrap-ansi@^7.0.0":
   version "7.0.0"
   resolved "https://registry.npmjs.org/wrap-ansi/-/wrap-ansi-7.0.0.tgz"
   integrity sha512-YVGIj2kamLSTxw6NsZjoBxfSwsn0ycdesmc4p+Q21c5zPuZ1pl+NfxVdxPtdHvmNVOQ6XSYG4AUtyt/Fi7D16Q==
@@ -7347,6 +7353,15 @@ wrap-ansi@^6.2.0:
     string-width "^4.1.0"
     strip-ansi "^6.0.0"
 
+wrap-ansi@^7.0.0:
+  version "7.0.0"
+  resolved "https://registry.npmjs.org/wrap-ansi/-/wrap-ansi-7.0.0.tgz"
+  integrity sha512-YVGIj2kamLSTxw6NsZjoBxfSwsn0ycdesmc4p+Q21c5zPuZ1pl+NfxVdxPtdHvmNVOQ6XSYG4AUtyt/Fi7D16Q==
+  dependencies:
+    ansi-styles "^4.0.0"
+    string-width "^4.1.0"
+    strip-ansi "^6.0.0"
+
 wrap-ansi@^8.1.0:
   version "8.1.0"
   resolved "https://registry.npmjs.org/wrap-ansi/-/wrap-ansi-8.1.0.tgz"