diff --git a/apps/browser/src/background/main.background.ts b/apps/browser/src/background/main.background.ts
index 707fa7b670..7ba55a4589 100644
--- a/apps/browser/src/background/main.background.ts
+++ b/apps/browser/src/background/main.background.ts
@@ -1483,6 +1483,7 @@ export default class MainBackground {
     await this.sdkLoadService.loadAndInit();
     // Only the "true" background should run migrations
     await this.migrationRunner.run();
+    this.encryptService.init(this.configService);
 
     // This is here instead of in the InitService b/c we don't plan for
     // side effects to run in the Browser InitService.
diff --git a/apps/browser/src/popup/services/init.service.ts b/apps/browser/src/popup/services/init.service.ts
index 1930dbd1d4..1de1731013 100644
--- a/apps/browser/src/popup/services/init.service.ts
+++ b/apps/browser/src/popup/services/init.service.ts
@@ -3,6 +3,8 @@ import { inject, Inject, Injectable } from "@angular/core";
 
 import { AbstractThemingService } from "@bitwarden/angular/platform/services/theming/theming.service.abstraction";
 import { TwoFactorService } from "@bitwarden/common/auth/abstractions/two-factor.service";
+import { EncryptService } from "@bitwarden/common/key-management/crypto/abstractions/encrypt.service";
+import { ConfigService } from "@bitwarden/common/platform/abstractions/config/config.service";
 import { I18nService } from "@bitwarden/common/platform/abstractions/i18n.service";
 import { LogService as LogServiceAbstraction } from "@bitwarden/common/platform/abstractions/log.service";
 import { PlatformUtilsService } from "@bitwarden/common/platform/abstractions/platform-utils.service";
@@ -29,6 +31,8 @@ export class InitService {
     private sdkLoadService: SdkLoadService,
     private viewCacheService: PopupViewCacheService,
     private readonly migrationRunner: MigrationRunner,
+    private configService: ConfigService,
+    private encryptService: EncryptService,
     @Inject(DOCUMENT) private document: Document,
   ) {}
 
@@ -40,6 +44,7 @@ export class InitService {
       this.twoFactorService.init();
       await this.viewCacheService.init();
       await this.sizeService.init();
+      this.encryptService.init(this.configService);
 
       const htmlEl = window.document.documentElement;
       this.themingService.applyThemeChangesTo(this.document);
diff --git a/apps/cli/src/service-container/service-container.ts b/apps/cli/src/service-container/service-container.ts
index 3453e0cff7..d10849bae0 100644
--- a/apps/cli/src/service-container/service-container.ts
+++ b/apps/cli/src/service-container/service-container.ts
@@ -984,6 +984,7 @@ export class ServiceContainer {
     this.containerService.attachToGlobal(global);
     await this.i18nService.init();
     this.twoFactorService.init();
+    this.encryptService.init(this.configService);
 
     // If a user has a BW_SESSION key stored in their env (not process.env.BW_SESSION),
     // this should set the user key to unlock the vault on init.
diff --git a/apps/desktop/src/app/services/init.service.ts b/apps/desktop/src/app/services/init.service.ts
index 6b511ff366..79c93c1390 100644
--- a/apps/desktop/src/app/services/init.service.ts
+++ b/apps/desktop/src/app/services/init.service.ts
@@ -9,6 +9,7 @@ import { AccountService } from "@bitwarden/common/auth/abstractions/account.serv
 import { TwoFactorService as TwoFactorServiceAbstraction } from "@bitwarden/common/auth/abstractions/two-factor.service";
 import { EncryptService } from "@bitwarden/common/key-management/crypto/abstractions/encrypt.service";
 import { DefaultVaultTimeoutService } from "@bitwarden/common/key-management/vault-timeout";
+import { ConfigService } from "@bitwarden/common/platform/abstractions/config/config.service";
 import { I18nService as I18nServiceAbstraction } from "@bitwarden/common/platform/abstractions/i18n.service";
 import { PlatformUtilsService as PlatformUtilsServiceAbstraction } from "@bitwarden/common/platform/abstractions/platform-utils.service";
 import { SdkLoadService } from "@bitwarden/common/platform/abstractions/sdk/sdk-load.service";
@@ -52,6 +53,7 @@ export class InitService {
     private autofillService: DesktopAutofillService,
     private autotypeService: DesktopAutotypeService,
     private sdkLoadService: SdkLoadService,
+    private configService: ConfigService,
     @Inject(DOCUMENT) private document: Document,
     private readonly migrationRunner: MigrationRunner,
   ) {}
@@ -62,6 +64,7 @@ export class InitService {
       await this.sshAgentService.init();
       this.nativeMessagingService.init();
       await this.migrationRunner.waitForCompletion(); // Desktop will run migrations in the main process
+      this.encryptService.init(this.configService);
 
       const accounts = await firstValueFrom(this.accountService.accounts$);
       const setUserKeyInMemoryPromises = [];
diff --git a/apps/web/src/app/core/init.service.ts b/apps/web/src/app/core/init.service.ts
index a3358ff725..6b03913ef7 100644
--- a/apps/web/src/app/core/init.service.ts
+++ b/apps/web/src/app/core/init.service.ts
@@ -9,6 +9,7 @@ import { AccountService } from "@bitwarden/common/auth/abstractions/account.serv
 import { TwoFactorService as TwoFactorServiceAbstraction } from "@bitwarden/common/auth/abstractions/two-factor.service";
 import { EncryptService } from "@bitwarden/common/key-management/crypto/abstractions/encrypt.service";
 import { DefaultVaultTimeoutService } from "@bitwarden/common/key-management/vault-timeout";
+import { ConfigService } from "@bitwarden/common/platform/abstractions/config/config.service";
 import { I18nService as I18nServiceAbstraction } from "@bitwarden/common/platform/abstractions/i18n.service";
 import { SdkLoadService } from "@bitwarden/common/platform/abstractions/sdk/sdk-load.service";
 import { IpcService } from "@bitwarden/common/platform/ipc";
@@ -40,6 +41,7 @@ export class InitService {
     private ipcService: IpcService,
     private sdkLoadService: SdkLoadService,
     private taskService: TaskService,
+    private configService: ConfigService,
     private readonly migrationRunner: MigrationRunner,
     @Inject(DOCUMENT) private document: Document,
   ) {}
@@ -48,6 +50,7 @@ export class InitService {
     return async () => {
       await this.sdkLoadService.loadAndInit();
       await this.migrationRunner.run();
+      this.encryptService.init(this.configService);
 
       const activeAccount = await firstValueFrom(this.accountService.activeAccount$);
       if (activeAccount) {
diff --git a/libs/common/src/enums/feature-flag.enum.ts b/libs/common/src/enums/feature-flag.enum.ts
index f6090c01d2..0ad63b630f 100644
--- a/libs/common/src/enums/feature-flag.enum.ts
+++ b/libs/common/src/enums/feature-flag.enum.ts
@@ -34,6 +34,7 @@ export enum FeatureFlag {
   PrivateKeyRegeneration = "pm-12241-private-key-regeneration",
   EnrollAeadOnKeyRotation = "enroll-aead-on-key-rotation",
   ForceUpdateKDFSettings = "pm-18021-force-update-kdf-settings",
+  PM25174_DisableType0Decryption = "pm-25174-disable-type-0-decryption",
   UnlockWithMasterPasswordUnlockData = "pm-23246-unlock-with-master-password-unlock-data",
 
   /* Tools */
@@ -113,6 +114,7 @@ export const DefaultFeatureFlagValue = {
   [FeatureFlag.PrivateKeyRegeneration]: FALSE,
   [FeatureFlag.EnrollAeadOnKeyRotation]: FALSE,
   [FeatureFlag.ForceUpdateKDFSettings]: FALSE,
+  [FeatureFlag.PM25174_DisableType0Decryption]: FALSE,
   [FeatureFlag.UnlockWithMasterPasswordUnlockData]: FALSE,
 
   /* Platform */
diff --git a/libs/common/src/key-management/crypto/abstractions/encrypt.service.ts b/libs/common/src/key-management/crypto/abstractions/encrypt.service.ts
index 87af385211..25e5f949b4 100644
--- a/libs/common/src/key-management/crypto/abstractions/encrypt.service.ts
+++ b/libs/common/src/key-management/crypto/abstractions/encrypt.service.ts
@@ -1,8 +1,16 @@
+import { ConfigService } from "@bitwarden/common/platform/abstractions/config/config.service";
+
 import { EncArrayBuffer } from "../../../platform/models/domain/enc-array-buffer";
 import { SymmetricCryptoKey } from "../../../platform/models/domain/symmetric-crypto-key";
 import { EncString } from "../models/enc-string";
 
 export abstract class EncryptService {
+  /**
+   * A temporary init method to make the encrypt service listen to feature-flag changes.
+   * This will be removed once the feature flag has been rolled out.
+   */
+  abstract init(configService: ConfigService): void;
+
   /**
    * Encrypts a string to an EncString
    * @param plainValue - The value to encrypt
diff --git a/libs/common/src/key-management/crypto/services/encrypt.service.implementation.ts b/libs/common/src/key-management/crypto/services/encrypt.service.implementation.ts
index 6daede6be6..132bbc306c 100644
--- a/libs/common/src/key-management/crypto/services/encrypt.service.implementation.ts
+++ b/libs/common/src/key-management/crypto/services/encrypt.service.implementation.ts
@@ -1,7 +1,9 @@
 // FIXME: Update this file to be type safe and remove this and next line
 // @ts-strict-ignore
+import { FeatureFlag } from "@bitwarden/common/enums/feature-flag.enum";
 import { CryptoFunctionService } from "@bitwarden/common/key-management/crypto/abstractions/crypto-function.service";
 import { EncString } from "@bitwarden/common/key-management/crypto/models/enc-string";
+import { ConfigService } from "@bitwarden/common/platform/abstractions/config/config.service";
 import { LogService } from "@bitwarden/common/platform/abstractions/log.service";
 import { SdkLoadService } from "@bitwarden/common/platform/abstractions/sdk/sdk-load.service";
 import { EncryptionType } from "@bitwarden/common/platform/enums";
@@ -13,12 +15,28 @@ import { PureCrypto } from "@bitwarden/sdk-internal";
 import { EncryptService } from "../abstractions/encrypt.service";
 
 export class EncryptServiceImplementation implements EncryptService {
+  private disableType0Decryption = false;
+
   constructor(
     protected cryptoFunctionService: CryptoFunctionService,
     protected logService: LogService,
     protected logMacFailures: boolean,
   ) {}
 
+  init(configService: ConfigService): void {
+    configService.serverConfig$.subscribe((newConfig) => {
+      if (newConfig != null) {
+        this.setDisableType0Decryption(
+          newConfig.featureStates[FeatureFlag.PM25174_DisableType0Decryption] === true,
+        );
+      }
+    });
+  }
+
+  setDisableType0Decryption(disable: boolean): void {
+    this.disableType0Decryption = disable;
+  }
+
   async encryptString(plainValue: string, key: SymmetricCryptoKey): Promise<EncString> {
     if (plainValue == null) {
       this.logService.warning(
@@ -42,16 +60,25 @@ export class EncryptServiceImplementation implements EncryptService {
   }
 
   async decryptString(encString: EncString, key: SymmetricCryptoKey): Promise<string> {
+    if (this.disableType0Decryption && encString.encryptionType === EncryptionType.AesCbc256_B64) {
+      throw new Error("Decryption of AesCbc256_B64 encrypted data is disabled.");
+    }
     await SdkLoadService.Ready;
     return PureCrypto.symmetric_decrypt_string(encString.encryptedString, key.toEncoded());
   }
 
   async decryptBytes(encString: EncString, key: SymmetricCryptoKey): Promise<Uint8Array> {
+    if (this.disableType0Decryption && encString.encryptionType === EncryptionType.AesCbc256_B64) {
+      throw new Error("Decryption of AesCbc256_B64 encrypted data is disabled.");
+    }
     await SdkLoadService.Ready;
     return PureCrypto.symmetric_decrypt_bytes(encString.encryptedString, key.toEncoded());
   }
 
   async decryptFileData(encBuffer: EncArrayBuffer, key: SymmetricCryptoKey): Promise<Uint8Array> {
+    if (this.disableType0Decryption && encBuffer.encryptionType === EncryptionType.AesCbc256_B64) {
+      throw new Error("Decryption of AesCbc256_B64 encrypted data is disabled.");
+    }
     await SdkLoadService.Ready;
     return PureCrypto.symmetric_decrypt_filedata(encBuffer.buffer, key.toEncoded());
   }
@@ -121,6 +148,13 @@ export class EncryptServiceImplementation implements EncryptService {
       throw new Error("No wrappingKey provided for unwrapping.");
     }
 
+    if (
+      this.disableType0Decryption &&
+      wrappedDecapsulationKey.encryptionType === EncryptionType.AesCbc256_B64
+    ) {
+      throw new Error("Decryption of AesCbc256_B64 encrypted data is disabled.");
+    }
+
     await SdkLoadService.Ready;
     return PureCrypto.unwrap_decapsulation_key(
       wrappedDecapsulationKey.encryptedString,
@@ -137,6 +171,12 @@ export class EncryptServiceImplementation implements EncryptService {
     if (wrappingKey == null) {
       throw new Error("No wrappingKey provided for unwrapping.");
     }
+    if (
+      this.disableType0Decryption &&
+      wrappedEncapsulationKey.encryptionType === EncryptionType.AesCbc256_B64
+    ) {
+      throw new Error("Decryption of AesCbc256_B64 encrypted data is disabled.");
+    }
 
     await SdkLoadService.Ready;
     return PureCrypto.unwrap_encapsulation_key(
@@ -154,6 +194,12 @@ export class EncryptServiceImplementation implements EncryptService {
     if (wrappingKey == null) {
       throw new Error("No wrappingKey provided for unwrapping.");
     }
+    if (
+      this.disableType0Decryption &&
+      keyToBeUnwrapped.encryptionType === EncryptionType.AesCbc256_B64
+    ) {
+      throw new Error("Decryption of AesCbc256_B64 encrypted data is disabled.");
+    }
 
     await SdkLoadService.Ready;
     return new SymmetricCryptoKey(
diff --git a/libs/common/src/key-management/crypto/services/encrypt.service.spec.ts b/libs/common/src/key-management/crypto/services/encrypt.service.spec.ts
index 0cc7824a91..466f59da7c 100644
--- a/libs/common/src/key-management/crypto/services/encrypt.service.spec.ts
+++ b/libs/common/src/key-management/crypto/services/encrypt.service.spec.ts
@@ -171,6 +171,15 @@ describe("EncryptService", () => {
         key.toEncoded(),
       );
     });
+
+    it("throws if disableType0Decryption is enabled and type is AesCbc256_B64", async () => {
+      encryptService.setDisableType0Decryption(true);
+      const key = new SymmetricCryptoKey(makeStaticByteArray(64));
+      const encString = new EncString(EncryptionType.AesCbc256_B64, "encrypted_string");
+      await expect(encryptService.decryptString(encString, key)).rejects.toThrow(
+        "Decryption of AesCbc256_B64 encrypted data is disabled.",
+      );
+    });
   });
 
   describe("decryptBytes", () => {
@@ -184,6 +193,15 @@ describe("EncryptService", () => {
         key.toEncoded(),
       );
     });
+
+    it("throws if disableType0Decryption is enabled and type is AesCbc256_B64", async () => {
+      encryptService.setDisableType0Decryption(true);
+      const key = new SymmetricCryptoKey(makeStaticByteArray(64));
+      const encString = new EncString(EncryptionType.AesCbc256_B64, "encrypted_bytes");
+      await expect(encryptService.decryptBytes(encString, key)).rejects.toThrow(
+        "Decryption of AesCbc256_B64 encrypted data is disabled.",
+      );
+    });
   });
 
   describe("decryptFileData", () => {
@@ -197,6 +215,20 @@ describe("EncryptService", () => {
         key.toEncoded(),
       );
     });
+
+    it("throws if disableType0Decryption is enabled and type is AesCbc256_B64", async () => {
+      encryptService.setDisableType0Decryption(true);
+      const key = new SymmetricCryptoKey(makeStaticByteArray(64));
+      const encBuffer = EncArrayBuffer.fromParts(
+        EncryptionType.AesCbc256_B64,
+        new Uint8Array(16),
+        new Uint8Array(32),
+        null,
+      );
+      await expect(encryptService.decryptFileData(encBuffer, key)).rejects.toThrow(
+        "Decryption of AesCbc256_B64 encrypted data is disabled.",
+      );
+    });
   });
 
   describe("unwrapDecapsulationKey", () => {
@@ -210,6 +242,14 @@ describe("EncryptService", () => {
         key.toEncoded(),
       );
     });
+    it("throws if disableType0Decryption is enabled and type is AesCbc256_B64", async () => {
+      encryptService.setDisableType0Decryption(true);
+      const key = new SymmetricCryptoKey(makeStaticByteArray(64));
+      const encString = new EncString(EncryptionType.AesCbc256_B64, "wrapped_decapsulation_key");
+      await expect(encryptService.unwrapDecapsulationKey(encString, key)).rejects.toThrow(
+        "Decryption of AesCbc256_B64 encrypted data is disabled.",
+      );
+    });
     it("throws if wrappedDecapsulationKey is null", () => {
       const key = new SymmetricCryptoKey(makeStaticByteArray(64));
       return expect(encryptService.unwrapDecapsulationKey(null, key)).rejects.toThrow(
@@ -235,6 +275,14 @@ describe("EncryptService", () => {
         key.toEncoded(),
       );
     });
+    it("throws if disableType0Decryption is enabled and type is AesCbc256_B64", async () => {
+      encryptService.setDisableType0Decryption(true);
+      const key = new SymmetricCryptoKey(makeStaticByteArray(64));
+      const encString = new EncString(EncryptionType.AesCbc256_B64, "wrapped_encapsulation_key");
+      await expect(encryptService.unwrapEncapsulationKey(encString, key)).rejects.toThrow(
+        "Decryption of AesCbc256_B64 encrypted data is disabled.",
+      );
+    });
     it("throws if wrappedEncapsulationKey is null", () => {
       const key = new SymmetricCryptoKey(makeStaticByteArray(64));
       return expect(encryptService.unwrapEncapsulationKey(null, key)).rejects.toThrow(
@@ -260,6 +308,14 @@ describe("EncryptService", () => {
         key.toEncoded(),
       );
     });
+    it("throws if disableType0Decryption is enabled and type is AesCbc256_B64", async () => {
+      encryptService.setDisableType0Decryption(true);
+      const key = new SymmetricCryptoKey(makeStaticByteArray(64));
+      const encString = new EncString(EncryptionType.AesCbc256_B64, "wrapped_symmetric_key");
+      await expect(encryptService.unwrapSymmetricKey(encString, key)).rejects.toThrow(
+        "Decryption of AesCbc256_B64 encrypted data is disabled.",
+      );
+    });
     it("throws if keyToBeUnwrapped is null", () => {
       const key = new SymmetricCryptoKey(makeStaticByteArray(64));
       return expect(encryptService.unwrapSymmetricKey(null, key)).rejects.toThrow(