diff --git a/docs/api/billing.md b/docs/api/billing.md
index bc4dc068..ae3397ae 100644
--- a/docs/api/billing.md
+++ b/docs/api/billing.md
@@ -163,11 +163,11 @@
 | action | body اختیاری | اثر |
 |--------|--------------|-----|
 | submit | — | pending → submitted |
-| approve | `approved_rials` | submitted → approved (پیش‌فرض = کل ادعا) |
+| approve | `approved_rials` | submitted → approved (پیش‌فرض = کل ادعا) — باید `0 ≤ approved_rials ≤ total_claimed_rials` |
 | reject | `reason` (الزامی) | submitted → rejected |
-| pay | `paid_rials` | approved → paid (پیش‌فرض = approved) |
+| pay | `paid_rials` | approved → paid (پیش‌فرض = approved) — باید `0 ≤ paid_rials ≤ total_approved_rials` |
 
-**Errors:** `422` انتقال نامعتبر یا دلیل رد خالی · `404` مطالبه یافت نشد.
+**Errors:** `422` انتقال نامعتبر، دلیل رد خالی، یا مبلغ `approved_rials`/`paid_rials` خارج از بازه (`field` در پاسخ) · `404` مطالبه یافت نشد.
 
 ## GET /api/v1/billing/reports/insurance-debt
 گزارش بدهی بیمه‌ها برای tenant (group بر اساس بیمه).
diff --git a/docs/audit-backlog.md b/docs/audit-backlog.md
index fcaf3d59..9edd9dd9 100644
--- a/docs/audit-backlog.md
+++ b/docs/audit-backlog.md
@@ -54,7 +54,7 @@ _None outstanding._
 
 | # | Task | File:line | Cat | How to test |
 |---|------|-----------|-----|-------------|
-| M1 | Mass-assign: claim approve/pay lets owning tenant set arbitrary `approved_rials`/`paid_rials` + force status PAID/APPROVED | src/Billing/Controller/BillingController.php:192 | security-massassign | POST claim approve w/ huge amounts → server computes, ignores caller figures |
+| ✅M1 | Mass-assign: claim approve/pay lets owning tenant set arbitrary `approved_rials`/`paid_rials` ~~+ force status~~ | src/Billing/Controller/BillingController.php | security-massassign | **DONE** — status-jump part was already guarded by `canTransitionTo` (false alarm). Added bounds: approved ∈ [0, claimed], paid ∈ [0, approved] → 422. `tests/Billing/ClaimAmountBoundsTest`. |
 | M2 | IDOR read: `GET /insurance/{id}` (showDoctorInsurance) leaks any doctor's insurance incl. negotiated price by id enumeration | src/Insurance/Controller/InsuranceController.php:499 | security-idor | GET insurance/{id} as non-owner → 403 |
 | M3 | IDOR read: `showAddress` loads any DoctorAddress by id, no owner check | src/Doctor/Controller/DoctorController.php:559 | security-idor | GET doctor-address/{id} as non-owner → 403 |
 | M4 | IDOR write: ClinicService `createItem`/`updateItem` bind staff via global `staffRepo->findByUuid()`, no entity-scope check (cross-tenant staff binding) | src/ClinicService/Controller/ClinicServiceController.php:157,195 | security-idor | Bind other clinic's staff_uuid → 403/validation |
diff --git a/src/Billing/Controller/BillingController.php b/src/Billing/Controller/BillingController.php
index 350b66ab..c8739cd2 100644
--- a/src/Billing/Controller/BillingController.php
+++ b/src/Billing/Controller/BillingController.php
@@ -224,6 +224,22 @@ class BillingController extends BaseController
             return $this->error(ErrorCodes::ERR_VALIDATION_001, 'دلیل رد الزامی است', 422);
         }
 
+        // Bound the financial figures: approved/paid cannot be negative, approved
+        // cannot exceed the claimed total, and paid cannot exceed approved.
+        if ($action === 'approve' && isset($data['approved_rials'])) {
+            $approved = (int) $data['approved_rials'];
+            if ($approved < 0 || $approved > $claim->getTotalClaimedRials()) {
+                return $this->error(ErrorCodes::ERR_VALIDATION_001, 'مبلغ تأییدشده باید بین ۰ و مبلغ مطالبه‌شده باشد', 422, 'approved_rials');
+            }
+        }
+        if ($action === 'pay' && isset($data['paid_rials'])) {
+            $paid    = (int) $data['paid_rials'];
+            $ceiling = $claim->getTotalApprovedRials() ?? $claim->getTotalClaimedRials();
+            if ($paid < 0 || $paid > $ceiling) {
+                return $this->error(ErrorCodes::ERR_VALIDATION_001, 'مبلغ پرداختی باید بین ۰ و مبلغ تأییدشده باشد', 422, 'paid_rials');
+            }
+        }
+
         $this->claimService->transition($claim, $target, [
             'approved_rials' => isset($data['approved_rials']) ? (int) $data['approved_rials'] : null,
             'paid_rials'     => isset($data['paid_rials']) ? (int) $data['paid_rials'] : null,
diff --git a/tests/Billing/ClaimAmountBoundsTest.php b/tests/Billing/ClaimAmountBoundsTest.php
new file mode 100644
index 00000000..4264a88d
--- /dev/null
+++ b/tests/Billing/ClaimAmountBoundsTest.php
@@ -0,0 +1,64 @@
+<?php
+
+namespace App\Tests\Billing;
+
+use App\Auth\Entity\User;
+use App\Billing\Entity\Claim;
+use App\Billing\Entity\ClaimItem;
+use App\Doctor\Entity\Doctor;
+use App\Tests\ApiTestCase;
+
+/**
+ * The claim approve/pay transition must bound the financial figures: approved
+ * cannot exceed the claimed total (nor be negative). Guards the insurer-debt
+ * ledger from arbitrary amounts entered by the claiming tenant.
+ */
+class ClaimAmountBoundsTest extends ApiTestCase
+{
+    private Doctor $doctor;
+    private User $owner;
+
+    private function submittedClaim(int $claimedRials): Claim
+    {
+        $claim = new Claim('doctor', $this->doctor->getId(), 1, 'base');
+        $item  = new ClaimItem($claim, 1, $claimedRials);
+        $claim->addItem($item);
+        $claim->submit();
+        $this->em->persist($claim);
+        $this->em->persist($item);
+        $this->em->flush();
+
+        return $claim;
+    }
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+        $this->owner  = $this->createUser(['ROLE_DOCTOR']);
+        $this->doctor = new Doctor($this->owner, 'دکتر تست');
+        $this->em->persist($this->doctor);
+        $this->em->flush();
+    }
+
+    public function testApproveAboveClaimedIsRejected(): void
+    {
+        $claim = $this->submittedClaim(100_000);
+
+        $this->authJson('POST', '/api/v1/billing/claims/' . $claim->getUuid() . '/approve', $this->owner, [
+            'approved_rials' => 999_999,
+        ]);
+
+        $this->assertSame(422, $this->responseCode());
+    }
+
+    public function testApproveWithinBoundsSucceeds(): void
+    {
+        $claim = $this->submittedClaim(100_000);
+
+        $this->authJson('POST', '/api/v1/billing/claims/' . $claim->getUuid() . '/approve', $this->owner, [
+            'approved_rials' => 60_000,
+        ]);
+
+        $this->assertSame(200, $this->responseCode());
+    }
+}