diff --git a/backend/src/main/java/th/co/glr/hr/deposit/DepositNoticeService.java b/backend/src/main/java/th/co/glr/hr/deposit/DepositNoticeService.java
index b2fa63925..da2d1c40a 100644
--- a/backend/src/main/java/th/co/glr/hr/deposit/DepositNoticeService.java
+++ b/backend/src/main/java/th/co/glr/hr/deposit/DepositNoticeService.java
@@ -102,6 +102,7 @@ public DepositNoticeDto createDraft(long ticketId, DepositNoticeDraftRequest req
     public DepositNoticeDto createDraftFromQuotation(long ticketId, DepositNoticeDraftRequest req,
                                                      Integer sourceDepositPercent, UserPrincipal actor) {
         requireRole(actor, SALES_ROLES);
+        requireTicketOwner(ticketId, actor);
         TicketSummaryDto s = requireApprovedTicket(ticketId, actor);
         requireActiveLifecycle(s);
 
diff --git a/backend/src/test/java/th/co/glr/hr/dealquotation/DealQuotationOutcomeIntegrationTest.java b/backend/src/test/java/th/co/glr/hr/dealquotation/DealQuotationOutcomeIntegrationTest.java
index 08b841ab7..1815e4db0 100644
--- a/backend/src/test/java/th/co/glr/hr/dealquotation/DealQuotationOutcomeIntegrationTest.java
+++ b/backend/src/test/java/th/co/glr/hr/dealquotation/DealQuotationOutcomeIntegrationTest.java
@@ -326,6 +326,34 @@ void createDepositNoticeFromQuotation_newEngine_nonOwnerSales_cannotReach() {
             Map.of("id", ticketId), Long.class)).isZero();
     }
 
+    /** The ticket route (POST /api/tickets/{id}/deposit-notice/draft) had no owner check, unlike
+     * update/issue: another rep could draft on this deal and read its lines, prices and customer. */
+    @Test
+    void createDraft_ticketRoute_byNonOwningSales_refusedAndWritesNothing() {
+        var emptyRequest = new DepositNoticeDraftRequest(null, null, null, null, null, null, null, null);
+        // Owner before status: a non-owner must not learn whether another rep's deal is approved yet
+        // (403 here, not the 409 the owner would get on this still-unapproved ticket).
+        assertThatThrownBy(() -> depositNoticeService.createDraft(ticketId, emptyRequest, otherSalesActor))
+            .isInstanceOf(ApiException.class)
+            .hasFieldOrPropertyWithValue("status", HttpStatus.FORBIDDEN);
+
+        DealQuotationDto accepted = acceptedNewOriginQuotation(PricingRequestRecipient.DESIGNER, new BigDecimal("10"));
+        orderConfirmation.confirmOrder(accepted.pricingRequestId(),
+            new OrderConfirmationRequests.ConfirmOrderRequest(UUID.randomUUID().toString()), salesActor);
+
+        assertThatThrownBy(() -> depositNoticeService.createDraft(ticketId, emptyRequest, otherSalesActor))
+            .isInstanceOf(ApiException.class)
+            .hasFieldOrPropertyWithValue("status", HttpStatus.FORBIDDEN)
+            .hasMessageContaining("ไม่มีสิทธิ์เข้าถึงรายการนี้");
+        assertThat(jdbc.queryForObject("SELECT COUNT(*) FROM sales.deposit_notice WHERE ticket_id = :id",
+            Map.of("id", ticketId), Long.class)).isZero();
+
+        // Positive control: the owner still drafts on the same deal.
+        assertThat(depositNoticeService.createDraft(ticketId, emptyRequest, salesActor).ticketId()).isEqualTo(ticketId);
+        assertThat(jdbc.queryForObject("SELECT COUNT(*) FROM sales.deposit_notice WHERE ticket_id = :id",
+            Map.of("id", ticketId), Long.class)).isEqualTo(1L);
+    }
+
     /** An open revision draft outranks the accepted quotation by id: recordOutcome has no
      * open-revision guard, so "latest for this pricing request" is not "accepted". */
     @Test
diff --git a/frontend/src/api/mockApi.depositNotices.test.js b/frontend/src/api/mockApi.depositNotices.test.js
index bc1a8e747..9e497e2a7 100644
--- a/frontend/src/api/mockApi.depositNotices.test.js
+++ b/frontend/src/api/mockApi.depositNotices.test.js
@@ -252,6 +252,24 @@ describe('mockApi.pricingRequests.createDepositNoticeFromQuotation — new-engin
     expect(pick(fromTicket.items)).toEqual(pick(fromPr.items));
   });
 
+  // Mirrors DepositNoticeService.createDraftFromQuotation's owner guard. sales2@glr.co.th is a
+  // second seeded sales rep; the drive above runs as the first one, who owns the deal.
+  it('ticket-level createDraft refuses a sales rep who does not own the deal and creates nothing', async () => {
+    const { ticketId } = await driveTicketToNewEngineAcceptedQuotation();
+    await api.auth.login({ email: 'sales2@glr.co.th', password: 'demo1234' });
+    await expect(api.depositNotices.createDraft(ticketId, {}))
+      .rejects.toMatchObject({ status: 403, message: 'ไม่มีสิทธิ์เข้าถึงรายการนี้' });
+    // Role gate (SALES_ROLES = sales only) runs before the ticket lookup, as in Java: a non-sales
+    // caller gets 403 even for a ticket that does not exist, never the 404.
+    await api.auth.login({ role: 'ceo' });
+    await expect(api.depositNotices.createDraft(999999, {})).rejects.toMatchObject({ status: 403 });
+
+    await api.auth.login({ role: 'sales' });
+    expect((await api.depositNotices.listByTicket(ticketId)).depositNotices).toHaveLength(0);
+    const { depositNotice } = await api.depositNotices.createDraft(ticketId, {});
+    expect(depositNotice.ticketId).toBe(ticketId);
+  });
+
   it('still 409s while the new-engine quotation is only ISSUED (customer has not accepted)', async () => {
     const { ticketId, prId } = await driveTicketToNewEngineIssuedQuotation();
     await expect(api.pricingRequests.createDepositNoticeFromQuotation(prId, {}))
diff --git a/frontend/src/api/mockApi.js b/frontend/src/api/mockApi.js
index d17302ee8..6e76f3ec5 100644
--- a/frontend/src/api/mockApi.js
+++ b/frontend/src/api/mockApi.js
@@ -13265,8 +13265,10 @@ export const api = {
     },
 
     async createDraft(ticketId, payload) {
-      requireSession();
+      // Mirrors DepositNoticeService.createDraftFromQuotation: requireRole(SALES_ROLES) + requireTicketOwner.
+      const user = hasRole('sales');
       const ticket = findTicketRaw(Number(ticketId));
+      if (ticket.createdById !== user.id) fail('ไม่มีสิทธิ์เข้าถึงรายการนี้', 403);
       // Phase 1 lifecycle gate (mirrors DepositNoticeService.createDraft).
       requireActive(ticket);
       if (!['approved', 'quotation_issued', 'document_issued'].includes(ticket.status)) fail('ดีลต้องได้รับการอนุมัติก่อน', 409);