diff --git a/README.en.md b/README.en.md
index d6a7427b..6b1aaa6b 100644
--- a/README.en.md
+++ b/README.en.md
@@ -150,7 +150,7 @@ Customers end up hopping between platforms, combining screenshots, edits, and ex
 
 - Production runs on a **home server (Mac mini, OrbStack)**.
   - The compose file in [`infra/`](./infra/) brings up api, worker, MySQL, Redis, RabbitMQ, the backup container, and the observability stack together.
-  - No inbound ports are opened; external traffic arrives only through a **Cloudflare Tunnel** (`api.caquick.site`).
+  - No inbound ports are opened; external traffic arrives only through a **Cloudflare Tunnel** (`api.caquick.com`).
 - **AWS S3**: media storage (presigned URL uploads) and daily database backups (14-day retention)
 - **Terraform**: S3 buckets, two least-privilege IAM users, and the GitHub repository and branch protection settings
 - Observability stack
diff --git a/README.md b/README.md
index 526a828c..1684bcfb 100644
--- a/README.md
+++ b/README.md
@@ -150,7 +150,7 @@
 
 - **홈서버(맥미니, OrbStack)** 가 운영 환경입니다.
   - [`infra/`](./infra/)의 compose 파일이 api·worker·MySQL·Redis·RabbitMQ·백업 컨테이너와 관측 스택을 함께 띄웁니다.
-  - 인바운드 포트는 열지 않으며, 외부 요청은 **Cloudflare Tunnel**(`api.caquick.site`)로만 들어옵니다.
+  - 인바운드 포트는 열지 않으며, 외부 요청은 **Cloudflare Tunnel**(`api.caquick.com`)로만 들어옵니다.
 - **AWS S3**: 미디어 저장(Presigned URL 업로드)과 일일 DB 백업(14일 보존)
 - **Terraform**: S3 버킷, 최소 권한 IAM 사용자 2개, GitHub 레포·브랜치 보호 설정
 - 관측 스택
diff --git a/infra/app.env.example b/infra/app.env.example
index 9ba651e3..1ae6082a 100644
--- a/infra/app.env.example
+++ b/infra/app.env.example
@@ -4,8 +4,8 @@
 
 # ---- 앱: 서버 ----
 NODE_ENV=production
-BACKEND_BASE_URL=https://api.caquick.site
-FRONTEND_BASE_URL=https://www.caquick.site
+BACKEND_BASE_URL=https://api.caquick.com
+FRONTEND_BASE_URL=https://caquick.com
 TRUST_PROXY_HOPS=1
 
 # ---- 앱: 연결(컨테이너 이름) ----
diff --git a/src/config/cors-origins.spec.ts b/src/config/cors-origins.spec.ts
index 059ffc8c..79914b86 100644
--- a/src/config/cors-origins.spec.ts
+++ b/src/config/cors-origins.spec.ts
@@ -12,6 +12,13 @@ describe('resolveAllowedOrigins', () => {
     expect(origins).not.toContain('http://evil.example');
   });
 
+  it.each(['https://caquick.com', 'https://admin.caquick.com'])(
+    '운영 목록은 새 도메인 오리진(%s)을 포함한다',
+    (origin) => {
+      expect(resolveAllowedOrigins(true, [])).toContain(origin);
+    },
+  );
+
   it.each([
     [['http://localhost:5173'], ['http://localhost:5173']],
     [
diff --git a/src/config/cors-origins.ts b/src/config/cors-origins.ts
index e25f4057..147af523 100644
--- a/src/config/cors-origins.ts
+++ b/src/config/cors-origins.ts
@@ -1,8 +1,11 @@
 /**
  * CORS 허용 오리진. 운영은 고정 목록(env로 바뀌지 않게), 비운영은 FRONTEND_BASE_URL 목록이고 비어 있으면 로컬 FE 기본값.
- * 관리자 웹(admin.caquick.site)은 refresh 쿠키가 same-site라 오리진만 열면 된다 — 쿠키 도메인 변경 불필요.
+ * 관리자 웹은 refresh 쿠키가 API와 same-site라 오리진만 열면 된다 — 쿠키 도메인 변경 불필요.
+ * caquick.site는 2026-11-29 만료까지 caquick.com과 병행한다(전환 전에 받은 페이지가 옛 API를 부른다).
  */
 export const PROD_ALLOWED_ORIGINS: readonly string[] = [
+  'https://caquick.com',
+  'https://admin.caquick.com',
   'https://www.caquick.site',
   'https://caquick.site',
   'https://caquick-fe.vercel.app',
diff --git a/src/features/auth/constants/auth.constants.ts b/src/features/auth/constants/auth.constants.ts
index 1da15d5c..dfb939b3 100644
--- a/src/features/auth/constants/auth.constants.ts
+++ b/src/features/auth/constants/auth.constants.ts
@@ -2,6 +2,7 @@ export const OIDC_TEMP_COOKIE_MAX_AGE_MS = 10 * 60 * 1000;
 
 /** 오픈 리다이렉트 방지. */
 export const ALLOWED_RETURN_TO_DOMAINS = [
+  'https://caquick.com',
   'https://www.caquick.site',
   'https://caquick.site',
   'http://localhost:3000',
diff --git a/src/features/auth/helpers/return-to.helper.spec.ts b/src/features/auth/helpers/return-to.helper.spec.ts
new file mode 100644
index 00000000..af8a79bc
--- /dev/null
+++ b/src/features/auth/helpers/return-to.helper.spec.ts
@@ -0,0 +1,40 @@
+import { resolveReturnTo } from '@/features/auth/helpers/return-to.helper';
+
+const FALLBACK = 'https://caquick.site';
+const ALLOWED = ['https://caquick.site', 'http://localhost:3000'];
+
+describe('resolveReturnTo', () => {
+  it.each([
+    ['https://caquick.site/mypage', 'https://caquick.site/mypage'],
+    ['http://localhost:3000/a?b=1', 'http://localhost:3000/a?b=1'],
+    ['  https://caquick.site/x  ', 'https://caquick.site/x'],
+  ])('허용 오리진이면 그 주소로 보낸다: %s', (raw, expected) => {
+    expect(resolveReturnTo(raw, FALLBACK, ALLOWED)).toBe(expected);
+  });
+
+  it.each([
+    ['접두가 같은 다른 호스트', 'https://caquick.site.evil.com/x'],
+    ['userinfo로 위장한 호스트', 'https://caquick.site@evil.com/x'],
+    ['이어 붙인 호스트', 'https://caquick.siteevil.com'],
+    ['스킴 불일치', 'http://caquick.site/x'],
+    ['포트 불일치', 'http://localhost:3001/x'],
+    ['스킴 상대 주소', '//evil.com'],
+    ['상대 경로', '/mypage'],
+    ['javascript 스킴', 'javascript:alert(1)'],
+    ['빈 문자열', ''],
+    ['공백', '   '],
+    ['undefined', undefined],
+  ])('%s(%s)는 기본 주소로 보낸다', (_label, raw) => {
+    expect(resolveReturnTo(raw, FALLBACK, ALLOWED)).toBe(FALLBACK);
+  });
+
+  it('기본 주소의 오리진은 허용 목록에 없어도 허용한다', () => {
+    expect(
+      resolveReturnTo(
+        'https://front.example/a',
+        'https://front.example',
+        ALLOWED,
+      ),
+    ).toBe('https://front.example/a');
+  });
+});
diff --git a/src/features/auth/helpers/return-to.helper.ts b/src/features/auth/helpers/return-to.helper.ts
new file mode 100644
index 00000000..422b2bcc
--- /dev/null
+++ b/src/features/auth/helpers/return-to.helper.ts
@@ -0,0 +1,24 @@
+/**
+ * 로그인 뒤 돌아갈 주소. 접두 비교는 `https://caquick.site.evil.com`·`https://caquick.site@evil.com`을 통과시키므로
+ * URL로 파싱해 오리진이 정확히 같을 때만 허용하고, 아니면 기본 프론트 주소로 보낸다.
+ */
+export function resolveReturnTo(
+  raw: string | undefined,
+  fallback: string,
+  allowed: readonly string[],
+): string {
+  const url = parseHttpUrl(raw?.trim() ?? '');
+  if (!url) return fallback;
+
+  const origins = [fallback, ...allowed].map((u) => parseHttpUrl(u)?.origin);
+  return origins.includes(url.origin) ? url.href : fallback;
+}
+
+function parseHttpUrl(raw: string): URL | null {
+  try {
+    const url = new URL(raw);
+    return url.protocol === 'https:' || url.protocol === 'http:' ? url : null;
+  } catch {
+    return null;
+  }
+}
diff --git a/src/features/auth/services/oidc-login.service.spec.ts b/src/features/auth/services/oidc-login.service.spec.ts
index 60e09041..ef6087e1 100644
--- a/src/features/auth/services/oidc-login.service.spec.ts
+++ b/src/features/auth/services/oidc-login.service.spec.ts
@@ -140,6 +140,26 @@ describe('OidcLoginService', () => {
       expect(returnToCookie![1]).toBe('http://localhost:3000');
     });
 
+    it.each(['https://caquick.com/mypage', 'https://caquick.site/mypage'])(
+      '운영 프론트 도메인 returnTo(%s)는 그대로 쓴다',
+      async (returnTo) => {
+        const mockRes = { cookie: jest.fn() } as unknown as Response;
+        mockOidc.buildAuthorizationUrl.mockResolvedValue({
+          authorizationUrl: 'https://a',
+          state: 's',
+          nonce: 'n',
+          codeVerifier: 'v',
+        });
+
+        await service.startOidcLogin('google', returnTo, mockRes);
+
+        const returnToCookie = (mockRes.cookie as jest.Mock).mock.calls.find(
+          (c) => c[0] === 'caquick_oidc_return_to',
+        );
+        expect(returnToCookie![1]).toBe(returnTo);
+      },
+    );
+
     it('returnTo가 undefined이면 기본 프론트 URL을 사용한다', async () => {
       const mockRes = { cookie: jest.fn() } as unknown as Response;
       mockConfig.getOrThrow.mockReturnValue(
diff --git a/src/features/auth/services/oidc-login.service.ts b/src/features/auth/services/oidc-login.service.ts
index 53bd0ec5..30c51a1c 100644
--- a/src/features/auth/services/oidc-login.service.ts
+++ b/src/features/auth/services/oidc-login.service.ts
@@ -7,6 +7,7 @@ import type { AuthConfig } from '@/config/auth.config';
 import { ALLOWED_RETURN_TO_DOMAINS } from '@/features/auth/constants/auth.constants';
 import { AuthCookieOptions } from '@/features/auth/helpers/auth-cookie-options.helper';
 import { AuthCookie } from '@/features/auth/helpers/auth-cookie.helper';
+import { resolveReturnTo } from '@/features/auth/helpers/return-to.helper';
 import {
   ACCOUNT_REPOSITORY,
   type IAccountRepository,
@@ -202,12 +203,7 @@ export class OidcLoginService {
   /** 오픈 리다이렉트 방지. */
   private normalizeReturnTo(raw: string | undefined): string {
     const frontend = this.config.getOrThrow<AuthConfig>('auth').frontendBaseUrl;
-
-    if (!raw || raw.trim().length === 0) return frontend;
-
-    const allowed = [frontend, ...ALLOWED_RETURN_TO_DOMAINS];
-    const ok = allowed.some((prefix) => raw.startsWith(prefix));
-    return ok ? raw : frontend;
+    return resolveReturnTo(raw, frontend, ALLOWED_RETURN_TO_DOMAINS);
   }
 
   private pickCallbackParams(req: Request): Record<string, string | string[]> {
diff --git a/terraform/aws.tf b/terraform/aws.tf
index 8ceee2b8..afe5c82c 100644
--- a/terraform/aws.tf
+++ b/terraform/aws.tf
@@ -92,7 +92,7 @@ resource "aws_s3_bucket_cors_configuration" "media" {
   cors_rule {
     allowed_headers = ["*"]
     allowed_methods = ["PUT", "GET"]
-    allowed_origins = ["http://localhost:3000", "http://localhost:5173", "https://www.caquick.site", "https://caquick.site", "https://admin.caquick.site"]
+    allowed_origins = ["http://localhost:3000", "http://localhost:5173", "https://caquick.com", "https://admin.caquick.com", "https://www.caquick.site", "https://caquick.site", "https://admin.caquick.site"]
     expose_headers  = ["ETag"]
     max_age_seconds = 3000
   }