diff --git a/BE/src/chat/chats.gateway.ts b/BE/src/chat/chats.gateway.ts
index b070772..fa45c04 100644
--- a/BE/src/chat/chats.gateway.ts
+++ b/BE/src/chat/chats.gateway.ts
@@ -25,14 +25,13 @@ export class ChatsGateway implements OnGatewayConnection, OnGatewayDisconnect {
   private readonly logger = new Logger('ChatsGateway');
   constructor(private readonly chatService: ChatService) {}
   handleConnection(client: ChatWebSocket, ...args) {
-    // const { authorization } = args[0].headers;
-    // const userId = this.chatService.validateUser(authorization);
-    // if (userId === null) {
-    //   client.close(1008, '토큰이 유효하지 않습니다.');
-    // }
-    // client.userId = userId;
-    // this.logger.debug(`[${userId}] on connect`, 'ChatsGateway');
-    this.logger.debug(`[] on connect`, 'ChatsGateway');
+    const { authorization } = args[0].headers;
+    const userId = this.chatService.validateUser(authorization);
+    if (userId === null) {
+      client.close(1008, '토큰이 유효하지 않습니다.');
+    }
+    client.userId = userId;
+    this.logger.debug(`[${userId}] on connect`, 'ChatsGateway');
   }
 
   handleDisconnect(client: ChatWebSocket) {
diff --git a/BE/src/post/post.controller.ts b/BE/src/post/post.controller.ts
index c70f809..6760229 100644
--- a/BE/src/post/post.controller.ts
+++ b/BE/src/post/post.controller.ts
@@ -4,7 +4,9 @@ import {
   Get,
   HttpCode,
   HttpException,
+  MaxFileSizeValidator,
   Param,
+  ParseFilePipe,
   Patch,
   Post,
   Query,
@@ -38,7 +40,12 @@ export class PostController {
   @Post()
   @UseInterceptors(FilesInterceptor('image', 12))
   async postsCreate(
-    @UploadedFiles() files: Array<Express.Multer.File>,
+    @UploadedFiles(
+      new ParseFilePipe({
+        validators: [new MaxFileSizeValidator({ maxSize: 1024 * 1024 * 20 })],
+      }),
+    )
+    files: Array<Express.Multer.File>,
     @MultiPartBody(
       'post_info',
       new ValidationPipe({ validateCustomDecorators: true }),
@@ -64,7 +71,11 @@ export class PostController {
   @UseInterceptors(FilesInterceptor('image', 12))
   async postModify(
     @Param('id') id: number,
-    @UploadedFiles()
+    @UploadedFiles(
+      new ParseFilePipe({
+        validators: [new MaxFileSizeValidator({ maxSize: 1024 * 1024 * 20 })],
+      }),
+    )
     files: Array<Express.Multer.File>,
     @MultiPartBody(
       'post_info',
diff --git a/BE/src/users/users.controller.ts b/BE/src/users/users.controller.ts
index 31ec611..179cd25 100644
--- a/BE/src/users/users.controller.ts
+++ b/BE/src/users/users.controller.ts
@@ -11,6 +11,8 @@ import {
   HttpException,
   UseGuards,
   Body,
+  ParseFilePipe,
+  MaxFileSizeValidator,
 } from '@nestjs/common';
 import { UsersService } from './users.service';
 import { CreateUserDto } from './createUser.dto';
@@ -38,7 +40,12 @@ export class UsersController {
   @Post()
   @UseInterceptors(FileInterceptor('profileImage'))
   async usersCreate(
-    @UploadedFile() file: Express.Multer.File,
+    @UploadedFile(
+      new ParseFilePipe({
+        validators: [new MaxFileSizeValidator({ maxSize: 1024 * 1024 * 20 })],
+      }),
+    )
+    file: Express.Multer.File,
     @MultiPartBody(
       'profile',
       new ValidationPipe({ validateCustomDecorators: true }),