diff --git a/plugins/_bundled/sirsoft-pay_nhnkcp/CHANGELOG.md b/plugins/_bundled/sirsoft-pay_nhnkcp/CHANGELOG.md
index f7563fcf..cce347b9 100644
--- a/plugins/_bundled/sirsoft-pay_nhnkcp/CHANGELOG.md
+++ b/plugins/_bundled/sirsoft-pay_nhnkcp/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 - 간편결제 주문의 원 결제수단이 사용자 주문완료/주문상세, 관리자 주문목록/주문상세에서 신용카드로만 보이지 않도록 표시 라벨과 관리자 목록 표시 맵을 보강했습니다.
 - 동일 주문의 NHN KCP 승인/가상계좌 콜백이 동시에 도착해도 결제완료 훅과 주문 부작용이 중복 실행되지 않도록 주문번호 단위 콜백 락을 추가했습니다.
+- 다통화 주문의 환율 스냅샷이 누락되거나 0인 경우 close-report, 재시도 API, 모바일 승인키, 승인 콜백에서 500 오류로 이어지지 않고 결제 통화 설정 오류로 명시 처리되도록 보강했습니다.
 - 결제창 닫힘, 인증 취소, 승인 실패, 금액 불일치 등 NHN KCP 실패 경로에서 주문 실패 상태와 결제 레코드의 PG별 실패 메타가 함께 기록되도록 보강했습니다.
 - 결제 실패/취소 후 같은 주문번호로 결제창을 다시 열 때 안전한 실패 주문만 `pending_order` / `ready` 상태로 복구하는 재시도 준비 API를 추가했습니다.
 - PC/모바일 결제창 호출 직전에 재시도 준비 API를 호출해 사용자가 결제 실패 후 동일 주문 결제를 다시 시도할 수 있도록 보강했습니다.
diff --git a/plugins/_bundled/sirsoft-pay_nhnkcp/src/Concerns/RecordsPaymentWindowClosure.php b/plugins/_bundled/sirsoft-pay_nhnkcp/src/Concerns/RecordsPaymentWindowClosure.php
index 7d4d0be6..ea971df7 100644
--- a/plugins/_bundled/sirsoft-pay_nhnkcp/src/Concerns/RecordsPaymentWindowClosure.php
+++ b/plugins/_bundled/sirsoft-pay_nhnkcp/src/Concerns/RecordsPaymentWindowClosure.php
@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace Plugins\Sirsoft\PayNhnkcp\Concerns;
 
+use InvalidArgumentException;
 use Illuminate\Http\Request;
 use Illuminate\Support\Facades\DB;
 use Illuminate\Support\Facades\Log;
@@ -26,6 +27,33 @@ trait RecordsPaymentWindowClosure
         return app(CurrencyConversionService::class)->resolveOrderPaymentChargeAmount($order);
     }
 
+    protected function resolveExpectedPaymentPriceOrNull(Order $order, string $context, array $logContext = []): ?int
+    {
+        try {
+            return $this->expectedPaymentPrice($order);
+        } catch (InvalidArgumentException $e) {
+            $this->logInvalidPaymentCurrency($order, $e, $context, $logContext);
+
+            return null;
+        }
+    }
+
+    protected function logInvalidPaymentCurrency(
+        Order $order,
+        InvalidArgumentException $e,
+        string $context,
+        array $logContext = [],
+    ): void {
+        Log::error('NHN KCP: payment currency is not chargeable', array_merge([
+            'context' => $context,
+            'order_id' => $order->id,
+            'order_number' => $order->order_number,
+            'currency' => $order->currency,
+            'currency_snapshot' => $order->currency_snapshot,
+            'error' => $e->getMessage(),
+        ], $logContext));
+    }
+
     protected function requestMatchesOrderBuyer(Request $request, Order $order): bool
     {
         /** @var OrderAddress|null $address */
@@ -129,8 +157,13 @@ trait RecordsPaymentWindowClosure
             return false;
         }
 
-        if ($amount !== null && $amount !== $this->expectedPaymentPrice($order)) {
-            return false;
+        if ($amount !== null) {
+            $expectedAmount = $this->resolveExpectedPaymentPriceOrNull($order, 'retry_restore', [
+                'received_amount' => $amount,
+            ]);
+            if ($expectedAmount === null || $amount !== $expectedAmount) {
+                return false;
+            }
         }
 
         if (! $this->isRetryableKcpFailure($order, $payment)) {
diff --git a/plugins/_bundled/sirsoft-pay_nhnkcp/src/Controllers/MobileApprovalController.php b/plugins/_bundled/sirsoft-pay_nhnkcp/src/Controllers/MobileApprovalController.php
index e82d91dc..2d122af9 100644
--- a/plugins/_bundled/sirsoft-pay_nhnkcp/src/Controllers/MobileApprovalController.php
+++ b/plugins/_bundled/sirsoft-pay_nhnkcp/src/Controllers/MobileApprovalController.php
@@ -119,7 +119,19 @@ class MobileApprovalController
                 ], 403);
             }
 
-            $expectedAmount = $this->expectedPaymentPrice($order);
+            $expectedAmount = $this->resolveExpectedPaymentPriceOrNull($order, 'mobile_approval_key', [
+                'order_number' => $validated['order_number'],
+                'requested_amount' => $validated['amount'],
+                'requested_currency' => $validated['currency'] ?? null,
+                'ip' => $request->ip(),
+            ]);
+            if ($expectedAmount === null) {
+                return response()->json([
+                    'success' => false,
+                    'error' => 'Payment currency is not chargeable.',
+                ], 422);
+            }
+
             if ((int) $validated['amount'] !== $expectedAmount) {
                 return response()->json([
                     'success' => false,
diff --git a/plugins/_bundled/sirsoft-pay_nhnkcp/src/Controllers/PaymentCallbackController.php b/plugins/_bundled/sirsoft-pay_nhnkcp/src/Controllers/PaymentCallbackController.php
index 345e0fc4..94e5f13f 100644
--- a/plugins/_bundled/sirsoft-pay_nhnkcp/src/Controllers/PaymentCallbackController.php
+++ b/plugins/_bundled/sirsoft-pay_nhnkcp/src/Controllers/PaymentCallbackController.php
@@ -16,7 +16,6 @@ use Modules\Sirsoft\Ecommerce\Enums\OrderStatusEnum;
 use Modules\Sirsoft\Ecommerce\Exceptions\PaymentAmountMismatchException;
 use Modules\Sirsoft\Ecommerce\Helpers\DeviceDetector;
 use Modules\Sirsoft\Ecommerce\Models\Order;
-use Modules\Sirsoft\Ecommerce\Services\CurrencyConversionService;
 use Modules\Sirsoft\Ecommerce\Services\OrderProcessingService;
 use Plugins\Sirsoft\PayNhnkcp\Concerns\PreventsReplayCallback;
 use Plugins\Sirsoft\PayNhnkcp\Concerns\RecordsPaymentWindowClosure;
@@ -221,7 +220,17 @@ class PaymentCallbackController
                 return redirect($this->resolveSuccessUrl($ordrIdxx));
             }
 
-            $expectedAmount = $this->expectedPaymentPrice($order);
+            $expectedAmount = $this->resolveExpectedPaymentPriceOrNull($order, 'auth_callback', [
+                'ordr_idxx' => $ordrIdxx,
+                'good_mny' => $goodMny,
+            ]);
+            if ($expectedAmount === null) {
+                return redirect($this->resolveFailUrl([
+                    'error' => 'invalid_payment_currency',
+                    'orderId' => $ordrIdxx,
+                ]));
+            }
+
             if (! $this->isKrwOrder($order)) {
                 Log::warning('KCP: unsupported order currency', [
                     'ordr_idxx' => $ordrIdxx,
@@ -303,7 +312,7 @@ class PaymentCallbackController
             // base≠결제 통화(예: base JPY, 결제 KRW)에서도 PG 청구 통화와 단위가 일치한다.
             $approvedAmt = $goodMny > 0
                 ? $goodMny
-                : app(CurrencyConversionService::class)->resolveOrderPaymentChargeAmount($order);
+                : $expectedAmount;
 
             // PG 측 승인이 확정된 시점 — 후속 처리 실패 시 cancel 필요. catch 에서 참조.
             $approvedTno = $tno;
@@ -771,6 +780,10 @@ class PaymentCallbackController
         }
 
         $expectedAmount = $this->expectedVbankNotifyAmount($order);
+        if ($expectedAmount === null) {
+            return 'invalid_payment_currency';
+        }
+
         if ($amount !== $expectedAmount) {
             return 'amount_mismatch';
         }
@@ -778,7 +791,7 @@ class PaymentCallbackController
         return null;
     }
 
-    private function expectedVbankNotifyAmount(Order $order): int
+    private function expectedVbankNotifyAmount(Order $order): ?int
     {
         $payment = $order->payment;
         $paidAmount = (int) round((float) ($payment?->paid_amount_local ?? 0));
@@ -787,7 +800,9 @@ class PaymentCallbackController
             return $paidAmount;
         }
 
-        return $this->expectedPaymentPrice($order);
+        return $this->resolveExpectedPaymentPriceOrNull($order, 'vbank_notify', [
+            'transaction_id' => $payment?->transaction_id,
+        ]);
     }
 
     /**
diff --git a/plugins/_bundled/sirsoft-pay_nhnkcp/src/Controllers/PaymentCloseReportController.php b/plugins/_bundled/sirsoft-pay_nhnkcp/src/Controllers/PaymentCloseReportController.php
index 5ecd20b1..459ec7b9 100644
--- a/plugins/_bundled/sirsoft-pay_nhnkcp/src/Controllers/PaymentCloseReportController.php
+++ b/plugins/_bundled/sirsoft-pay_nhnkcp/src/Controllers/PaymentCloseReportController.php
@@ -56,7 +56,18 @@ class PaymentCloseReportController
             ]);
         }
 
-        if ($price !== $this->expectedPaymentPrice($order)) {
+        $expectedPrice = $this->resolveExpectedPaymentPriceOrNull($order, 'close_report', [
+            'oid' => $oid,
+            'received_price' => $price,
+            'ip' => $request->ip(),
+        ]);
+        if ($expectedPrice === null) {
+            return ResponseHelper::error('messages.failed', 422, [
+                'message' => ['Payment currency is not chargeable.'],
+            ]);
+        }
+
+        if ($price !== $expectedPrice) {
             return ResponseHelper::error('messages.failed', 422, [
                 'message' => ['Payment amount does not match the order amount.'],
             ]);
diff --git a/plugins/_bundled/sirsoft-pay_nhnkcp/src/Controllers/PaymentRetryController.php b/plugins/_bundled/sirsoft-pay_nhnkcp/src/Controllers/PaymentRetryController.php
index 60503458..a5e115d4 100644
--- a/plugins/_bundled/sirsoft-pay_nhnkcp/src/Controllers/PaymentRetryController.php
+++ b/plugins/_bundled/sirsoft-pay_nhnkcp/src/Controllers/PaymentRetryController.php
@@ -52,7 +52,18 @@ class PaymentRetryController
             ]);
         }
 
-        if ($price !== $this->expectedPaymentPrice($order)) {
+        $expectedPrice = $this->resolveExpectedPaymentPriceOrNull($order, 'payment_retry', [
+            'oid' => $oid,
+            'received_price' => $price,
+            'ip' => $request->ip(),
+        ]);
+        if ($expectedPrice === null) {
+            return ResponseHelper::error('messages.failed', 422, [
+                'message' => ['Payment currency is not chargeable.'],
+            ]);
+        }
+
+        if ($price !== $expectedPrice) {
             return ResponseHelper::error('messages.failed', 422, [
                 'message' => ['Payment amount does not match the order amount.'],
             ]);
diff --git a/plugins/_bundled/sirsoft-pay_nhnkcp/tests/Feature/Controllers/MobileApprovalControllerTest.php b/plugins/_bundled/sirsoft-pay_nhnkcp/tests/Feature/Controllers/MobileApprovalControllerTest.php
index a486f0ba..570df6ed 100644
--- a/plugins/_bundled/sirsoft-pay_nhnkcp/tests/Feature/Controllers/MobileApprovalControllerTest.php
+++ b/plugins/_bundled/sirsoft-pay_nhnkcp/tests/Feature/Controllers/MobileApprovalControllerTest.php
@@ -73,6 +73,31 @@ class MobileApprovalControllerTest extends PluginTestCase
         ];
     }
 
+    private static function invalidUsdCurrencySnapshot(): array
+    {
+        return [
+            'base_currency' => 'KRW',
+            'order_currency' => 'USD',
+            'base_unit' => 1000,
+            'exchange_rates' => [
+                'KRW' => [
+                    'rate' => 1,
+                    'rounding_unit' => '1',
+                    'rounding_method' => 'round',
+                    'decimal_places' => 0,
+                    'base_unit' => 1000,
+                ],
+                'USD' => [
+                    'rate' => 0,
+                    'rounding_unit' => '0.01',
+                    'rounding_method' => 'round',
+                    'decimal_places' => 2,
+                    'base_unit' => 1,
+                ],
+            ],
+        ];
+    }
+
     private function mockSoapService(string $approvalKey = 'TEST_APPROVAL_KEY'): void
     {
         $mock = $this->createMock(KcpSoapService::class);
@@ -237,6 +262,24 @@ class MobileApprovalControllerTest extends PluginTestCase
             ->assertJsonPath('success', false);
     }
 
+    public function test_get_approval_key_rejects_invalid_payment_currency_without_server_error(): void
+    {
+        $order = $this->createOrder(10000);
+        $order->update([
+            'currency' => 'USD',
+            'currency_snapshot' => self::invalidUsdCurrencySnapshot(),
+        ]);
+        $this->expectSoapServiceNotCalled();
+        $this->mockPluginSettings();
+
+        $response = $this->actingAs($order->user)
+            ->postJson(self::APPROVAL_KEY_ENDPOINT, $this->approvalKeyPayload($order, ['currency' => 'USD']));
+
+        $response->assertUnprocessable()
+            ->assertJsonPath('success', false)
+            ->assertJsonPath('error', 'Payment currency is not chargeable.');
+    }
+
     public function test_get_approval_key_rejects_non_krw_order(): void
     {
         $order = $this->createOrder(10000);
diff --git a/plugins/_bundled/sirsoft-pay_nhnkcp/tests/Feature/Controllers/PaymentCallbackControllerTest.php b/plugins/_bundled/sirsoft-pay_nhnkcp/tests/Feature/Controllers/PaymentCallbackControllerTest.php
index 53992cd4..6250299b 100644
--- a/plugins/_bundled/sirsoft-pay_nhnkcp/tests/Feature/Controllers/PaymentCallbackControllerTest.php
+++ b/plugins/_bundled/sirsoft-pay_nhnkcp/tests/Feature/Controllers/PaymentCallbackControllerTest.php
@@ -109,6 +109,31 @@ class PaymentCallbackControllerTest extends PluginTestCase
         ];
     }
 
+    private static function invalidUsdCurrencySnapshot(): array
+    {
+        return [
+            'base_currency' => 'KRW',
+            'order_currency' => 'USD',
+            'base_unit' => 1000,
+            'exchange_rates' => [
+                'KRW' => [
+                    'rate' => 1,
+                    'rounding_unit' => '1',
+                    'rounding_method' => 'round',
+                    'decimal_places' => 0,
+                    'base_unit' => 1000,
+                ],
+                'USD' => [
+                    'rate' => 0,
+                    'rounding_unit' => '0.01',
+                    'rounding_method' => 'round',
+                    'decimal_places' => 2,
+                    'base_unit' => 1,
+                ],
+            ],
+        ];
+    }
+
     private function mockPluginSettings(array $overrides = []): void
     {
         $defaults = [
@@ -314,6 +339,32 @@ class PaymentCallbackControllerTest extends PluginTestCase
         $this->assertEquals(OrderStatusEnum::PENDING_ORDER, $order->order_status);
     }
 
+    public function test_auth_callback_rejects_invalid_payment_currency_before_cli_approval(): void
+    {
+        $order = $this->createTestOrder(50000);
+        $order->update([
+            'currency' => 'USD',
+            'currency_snapshot' => self::invalidUsdCurrencySnapshot(),
+        ]);
+        $this->mockPluginSettings();
+
+        $mock = $this->createMock(NhnKcpApiService::class);
+        $mock->expects($this->never())->method('approvePayment');
+        $this->app->instance(NhnKcpApiService::class, $mock);
+
+        $response = $this->post(
+            '/plugins/sirsoft-pay_nhnkcp/payment/callback',
+            $this->makeCallbackParams($order->order_number, 50000)
+        );
+
+        $response->assertRedirect();
+        $this->assertStringContainsString('error=invalid_payment_currency', $response->headers->get('Location'));
+
+        $order->refresh();
+        $this->assertEquals(OrderStatusEnum::PENDING_ORDER, $order->order_status);
+        $this->assertEquals(PaymentStatusEnum::READY, $order->payment->payment_status);
+    }
+
     public function test_auth_callback_stores_only_sanitized_pg_response_fields(): void
     {
         $order = $this->createTestOrder(50000);
diff --git a/plugins/_bundled/sirsoft-pay_nhnkcp/tests/Feature/Controllers/PaymentCloseReportControllerTest.php b/plugins/_bundled/sirsoft-pay_nhnkcp/tests/Feature/Controllers/PaymentCloseReportControllerTest.php
index e37255ef..bcc22976 100644
--- a/plugins/_bundled/sirsoft-pay_nhnkcp/tests/Feature/Controllers/PaymentCloseReportControllerTest.php
+++ b/plugins/_bundled/sirsoft-pay_nhnkcp/tests/Feature/Controllers/PaymentCloseReportControllerTest.php
@@ -74,6 +74,31 @@ class PaymentCloseReportControllerTest extends PluginTestCase
             ->assertJsonPath('errors.message.0', 'Payment amount does not match the order amount.');
     }
 
+    public function test_close_report_rejects_invalid_payment_currency_without_server_error(): void
+    {
+        $order = $this->makeOrder('ORD-KCP-CLOSE-CURRENCY-001', 10000);
+        $order->currency = 'USD';
+        $order->currency_snapshot = self::invalidUsdCurrencySnapshot();
+
+        $orderService = Mockery::mock(OrderProcessingService::class);
+        $orderService->shouldReceive('findByOrderNumber')
+            ->once()
+            ->with('ORD-KCP-CLOSE-CURRENCY-001')
+            ->andReturn($order);
+        $orderService->shouldNotReceive('failPayment');
+        $orderService->shouldNotReceive('recordPaymentCancellation');
+
+        $this->app->instance(OrderProcessingService::class, $orderService);
+
+        $response = $this->postJson('/api/plugins/sirsoft-pay_nhnkcp/payment/close-report', [
+            'oid' => 'ORD-KCP-CLOSE-CURRENCY-001',
+            'price' => 10000,
+        ]);
+
+        $response->assertStatus(422)
+            ->assertJsonPath('errors.message.0', 'Payment currency is not chargeable.');
+    }
+
     public function test_close_report_rejects_buyer_mismatch(): void
     {
         $order = $this->makeOrder('ORD-KCP-CLOSE-003', 10000);
@@ -186,4 +211,29 @@ class PaymentCloseReportControllerTest extends PluginTestCase
             ],
         ];
     }
+
+    private static function invalidUsdCurrencySnapshot(): array
+    {
+        return [
+            'base_currency' => 'KRW',
+            'order_currency' => 'USD',
+            'base_unit' => 1000,
+            'exchange_rates' => [
+                'KRW' => [
+                    'rate' => 1,
+                    'rounding_unit' => '1',
+                    'rounding_method' => 'round',
+                    'decimal_places' => 0,
+                    'base_unit' => 1000,
+                ],
+                'USD' => [
+                    'rate' => 0,
+                    'rounding_unit' => '0.01',
+                    'rounding_method' => 'round',
+                    'decimal_places' => 2,
+                    'base_unit' => 1,
+                ],
+            ],
+        ];
+    }
 }
diff --git a/plugins/_bundled/sirsoft-pay_nhnkcp/tests/Feature/Controllers/PaymentRetryControllerTest.php b/plugins/_bundled/sirsoft-pay_nhnkcp/tests/Feature/Controllers/PaymentRetryControllerTest.php
index 94177d2e..4149bef5 100644
--- a/plugins/_bundled/sirsoft-pay_nhnkcp/tests/Feature/Controllers/PaymentRetryControllerTest.php
+++ b/plugins/_bundled/sirsoft-pay_nhnkcp/tests/Feature/Controllers/PaymentRetryControllerTest.php
@@ -72,6 +72,31 @@ class PaymentRetryControllerTest extends PluginTestCase
         ];
     }
 
+    private static function invalidUsdCurrencySnapshot(): array
+    {
+        return [
+            'base_currency' => 'KRW',
+            'order_currency' => 'USD',
+            'base_unit' => 1000,
+            'exchange_rates' => [
+                'KRW' => [
+                    'rate' => 1,
+                    'rounding_unit' => '1',
+                    'rounding_method' => 'round',
+                    'decimal_places' => 0,
+                    'base_unit' => 1000,
+                ],
+                'USD' => [
+                    'rate' => 0,
+                    'rounding_unit' => '0.01',
+                    'rounding_method' => 'round',
+                    'decimal_places' => 2,
+                    'base_unit' => 1,
+                ],
+            ],
+        ];
+    }
+
     public function test_retry_returns_ready_for_pending_order(): void
     {
         $order = $this->createOrder(10000);
@@ -89,6 +114,27 @@ class PaymentRetryControllerTest extends PluginTestCase
         $this->assertEquals(PaymentStatusEnum::READY, $order->payment->payment_status);
     }
 
+    public function test_retry_rejects_invalid_payment_currency_without_server_error(): void
+    {
+        $order = $this->createOrder(10000);
+        $order->update([
+            'currency' => 'USD',
+            'currency_snapshot' => self::invalidUsdCurrencySnapshot(),
+        ]);
+
+        $response = $this->postJson(self::ENDPOINT, [
+            'oid' => $order->order_number,
+            'price' => 10000,
+        ]);
+
+        $response->assertStatus(422)
+            ->assertJsonPath('errors.message.0', 'Payment currency is not chargeable.');
+
+        $order->refresh();
+        $this->assertEquals(OrderStatusEnum::PENDING_ORDER, $order->order_status);
+        $this->assertEquals(PaymentStatusEnum::READY, $order->payment->payment_status);
+    }
+
     public function test_retry_restores_cancelled_kcp_failure_order(): void
     {
         $order = $this->createOrder(