diff --git a/__tests__/components/logout-postcondition.property.test.tsx b/__tests__/components/logout-postcondition.property.test.tsx
index ef145fc..7ff19ab 100644
--- a/__tests__/components/logout-postcondition.property.test.tsx
+++ b/__tests__/components/logout-postcondition.property.test.tsx
@@ -74,14 +74,29 @@ const userArbitrary: fc.Arbitrary<User> = fc.record({
 });
 
 describe("Feature: auth-flow-improvements, Property 12: Logout post-condition invariant", () => {
+  let originalLocation: Location;
+
   beforeEach(() => {
     mockSignout.mockReset();
     mockReplace.mockReset();
     sessionStorage.clear();
+    // 원본 location 보관 후, href 기록 가능한 스텁으로 교체
+    originalLocation = window.location;
+    Object.defineProperty(window, "location", {
+      configurable: true,
+      writable: true,
+      value: { ...originalLocation, href: "" },
+    });
   });
 
   afterEach(() => {
     cleanup();
+    // 원본 location getter 완전 복원
+    Object.defineProperty(window, "location", {
+      configurable: true,
+      writable: true,
+      value: originalLocation,
+    });
   });
 
   it(
@@ -108,12 +123,12 @@ describe("Feature: auth-flow-improvements, Property 12: Logout post-condition in
             render(<UserSetting />);
 
             // Find and click the logout button
-            const logoutButton = screen.getByText("로그아웃");
+            const logoutButton = screen.getByRole("button", { name: /로그아웃/ });
             fireEvent.click(logoutButton);
 
-            // Wait for the handler to complete
+            // Wait for the handler to complete (window.location.href 설정 확인)
             await waitFor(() => {
-              expect(mockReplace).toHaveBeenCalledWith("/");
+              expect(window.location.href).toBe("/");
             });
 
             // Post-condition: store.user SHALL be null
@@ -123,7 +138,7 @@ describe("Feature: auth-flow-improvements, Property 12: Logout post-condition in
             expect(sessionStorage.getItem(SESSION_CACHE_KEY)).toBeNull();
 
             cleanup();
-            mockReplace.mockReset();
+            window.location.href = "";
           }
         ),
         { numRuns: 100 }
diff --git a/components/pages/config/user-setting.tsx b/components/pages/config/user-setting.tsx
index 57d53b0..f736730 100644
--- a/components/pages/config/user-setting.tsx
+++ b/components/pages/config/user-setting.tsx
@@ -19,7 +19,10 @@ const UserSetting = () => {
     setUser(null);
     clearSessionCache();
 
-    // 2. 서버 로그아웃 API 호출 (5초 타임아웃, 실패해도 진행)
+    // 2. 서버 로그아웃 API 호출
+    //    signout은 keepalive:true라서 이후 하드 네비게이션으로 페이지가
+    //    언로드되어도 요청이 취소되지 않고 서버 세션 무효화가 보장된다.
+    //    UX 지연 방지를 위해 최대 5초까지만 대기한다.
     try {
       await Promise.race([
         signout(),
@@ -28,11 +31,11 @@ const UserSetting = () => {
         ),
       ]);
     } catch {
-      // API 실패 또는 타임아웃: 무시하고 진행
+      // API 실패 또는 타임아웃: keepalive 요청은 백그라운드에서 계속 진행
     }
 
-    // 3. 홈으로 이동
-    router.replace("/");
+    // 3. 홈으로 이동 (하드 네비게이션 — Next.js Router Cache 무효화)
+    window.location.href = "/";
   };
 
   const handleResign = () => {
diff --git a/components/pages/signin/signin-form.tsx b/components/pages/signin/signin-form.tsx
index bfe6de2..c6eeff6 100644
--- a/components/pages/signin/signin-form.tsx
+++ b/components/pages/signin/signin-form.tsx
@@ -103,8 +103,8 @@ const SigninForm = ({ returnUrl }: SinginFormProps) => {
         returnUrl && returnUrl.startsWith("/") && !returnUrl.startsWith("//")
           ? returnUrl
           : "/";
-      router.replace(targetUrl);
-      router.refresh();
+      // 하드 네비게이션: 미들웨어가 새 쿠키를 확실히 인식하도록
+      window.location.href = targetUrl;
     } catch (error) {
       // FetchError: 로그인 실패(401/400)도 여기로 옴 (fetchData가 non-OK에서 throw)
       if (error instanceof FetchError) {
@@ -125,7 +125,7 @@ const SigninForm = ({ returnUrl }: SinginFormProps) => {
       }
       setLoading(false);
     }
-  }, [emailValue.value, passwordValue.value, loading, errors, router, returnUrl, setUser, toast]);
+  }, [emailValue.value, passwordValue.value, loading, errors, returnUrl, setUser, toast]);
 
   // Enter 키 핸들러
   useEffect(() => {
diff --git a/lib/api/auth/signout.ts b/lib/api/auth/signout.ts
index ee6ef08..4cf9478 100644
--- a/lib/api/auth/signout.ts
+++ b/lib/api/auth/signout.ts
@@ -4,6 +4,8 @@ const signout = async () => {
   const response = await fetchData(`/api/v1/auth/logout`, {
     method: "POST",
     credentials: "include",
+    // 페이지가 언로드(하드 네비게이션)되어도 요청이 취소되지 않도록 보장
+    keepalive: true,
   });
 
   const data = response.json();