diff --git a/src/lib/services/documents.service.ts b/src/lib/services/documents.service.ts
index 94ec46f6..d0b9d821 100644
--- a/src/lib/services/documents.service.ts
+++ b/src/lib/services/documents.service.ts
@@ -41,6 +41,7 @@ import {
   type FolderNode,
   type EntityType,
 } from '@/lib/services/document-folders.service';
+import { assertEntityInPort, collectRelatedEntities } from '@/lib/services/files';
 import type {
   CreateDocumentInput,
   UpdateDocumentInput,
@@ -1822,8 +1823,6 @@ export async function createFromUpload(
 
 // ─── Aggregated Workflow Projection ───────────────────────────────────────────
 
-import { collectRelatedEntities } from '@/lib/services/files';
-
 export interface AggregatedWorkflowGroup {
   label: string;
   source: 'direct' | 'client' | 'company' | 'yacht';
@@ -1844,6 +1843,9 @@ export async function listInflightWorkflowsAggregatedByEntity(
   entityType: 'client' | 'company' | 'yacht',
   entityId: string,
 ): Promise<{ groups: AggregatedWorkflowGroup[] }> {
+  const entityExists = await assertEntityInPort(portId, entityType, entityId);
+  if (!entityExists) return { groups: [] };
+
   const related = await collectRelatedEntities(portId, entityType, entityId);
   const groups: AggregatedWorkflowGroup[] = [];
 
@@ -1910,11 +1912,7 @@ async function fetchWorkflowGroupRows(
     .select()
     .from(documents)
     .where(
-      and(
-        eq(documents.portId, portId),
-        inArray(documents.status, inflightStatuses),
-        predicate,
-      ),
+      and(eq(documents.portId, portId), inArray(documents.status, inflightStatuses), predicate),
     )
     .orderBy(desc(documents.updatedAt))
     .limit(WORKFLOW_GROUP_LIMIT);
@@ -1923,11 +1921,7 @@ async function fetchWorkflowGroupRows(
     .select({ count: sql<number>`count(*)::int` })
     .from(documents)
     .where(
-      and(
-        eq(documents.portId, portId),
-        inArray(documents.status, inflightStatuses),
-        predicate,
-      ),
+      and(eq(documents.portId, portId), inArray(documents.status, inflightStatuses), predicate),
     );
 
   return { rows, total: Number(countRow?.count ?? 0) };
diff --git a/src/lib/services/files.ts b/src/lib/services/files.ts
index fb3a35e1..52e33b10 100644
--- a/src/lib/services/files.ts
+++ b/src/lib/services/files.ts
@@ -1,4 +1,4 @@
-import { and, arrayContains, desc, eq, inArray, or, sql } from 'drizzle-orm';
+import { and, arrayContains, desc, eq, inArray, isNull, or, sql } from 'drizzle-orm';
 
 import { db } from '@/lib/db';
 import { files, documents } from '@/lib/db/schema/documents';
@@ -364,7 +364,7 @@ export async function listFilesAggregatedByEntity(
   return { groups };
 }
 
-async function assertEntityInPort(
+export async function assertEntityInPort(
   portId: string,
   entityType: EntityType,
   entityId: string,
@@ -415,7 +415,9 @@ export async function collectRelatedEntities(
         companies,
         and(eq(companies.id, companyMemberships.companyId), eq(companies.portId, portId)),
       )
-      .where(eq(companyMemberships.clientId, entityId));
+      .where(
+        and(eq(companyMemberships.clientId, entityId), isNull(companyMemberships.endDate)),
+      );
 
     const directYachts = await db
       .select({ id: yachts.id, name: yachts.name })
@@ -461,7 +463,9 @@ export async function collectRelatedEntities(
         clients,
         and(eq(clients.id, companyMemberships.clientId), eq(clients.portId, portId)),
       )
-      .where(eq(companyMemberships.companyId, entityId));
+      .where(
+        and(eq(companyMemberships.companyId, entityId), isNull(companyMemberships.endDate)),
+      );
 
     const ownedYachts = await db
       .select({ id: yachts.id, name: yachts.name })
@@ -561,10 +565,7 @@ export async function applyEntityFkFromFolder<
   if (!payload.folderId) return payload;
 
   const folder = await db.query.documentFolders.findFirst({
-    where: and(
-      eq(documentFolders.id, payload.folderId),
-      eq(documentFolders.portId, portId),
-    ),
+    where: and(eq(documentFolders.id, payload.folderId), eq(documentFolders.portId, portId)),
     columns: { systemManaged: true, entityType: true, entityId: true },
   });
 
diff --git a/tests/unit/aggregated-projection.test.ts b/tests/unit/aggregated-projection.test.ts
index 217fe55a..830c59a3 100644
--- a/tests/unit/aggregated-projection.test.ts
+++ b/tests/unit/aggregated-projection.test.ts
@@ -16,16 +16,11 @@ import { and, eq } from 'drizzle-orm';
 
 import { db } from '@/lib/db';
 import { files, documents, documentFolders } from '@/lib/db/schema/documents';
+import { clients } from '@/lib/db/schema/clients';
 import { user } from '@/lib/db/schema/users';
 import { yachts } from '@/lib/db/schema/yachts';
-import {
-  ensureSystemRoots,
-  ensureEntityFolder,
-} from '@/lib/services/document-folders.service';
-import {
-  listFilesAggregatedByEntity,
-  applyEntityFkFromFolder,
-} from '@/lib/services/files';
+import { ensureSystemRoots, ensureEntityFolder } from '@/lib/services/document-folders.service';
+import { listFilesAggregatedByEntity, applyEntityFkFromFolder } from '@/lib/services/files';
 import { listInflightWorkflowsAggregatedByEntity } from '@/lib/services/documents.service';
 import { makePort, makeClient, makeCompany, makeYacht, makeMembership } from '../helpers/factories';
 
@@ -133,9 +128,7 @@ describe('files service · listFilesAggregatedByEntity', () => {
       clientId = client.id;
 
       // Insert 25 files all with clientId
-      await Promise.all(
-        Array.from({ length: 25 }, () => insertFile(portId, { clientId })),
-      );
+      await Promise.all(Array.from({ length: 25 }, () => insertFile(portId, { clientId })));
     });
 
     it('DIRECTLY ATTACHED group has 20 files and total=25', async () => {
@@ -265,6 +258,16 @@ describe('documents service · listInflightWorkflowsAggregatedByEntity', () => {
     expect(directGroup!.workflows[0]!.status).toBe('sent');
     expect(directGroup!.workflows[0]!.title).toBe('In-flight Doc');
   });
+
+  it('rejects cross-port leakage with defense-in-depth port filter', async () => {
+    const otherPort = await makePort();
+    const [otherClient] = await db
+      .insert(clients)
+      .values({ portId: otherPort.id, fullName: 'Other Port Client' })
+      .returning();
+    const result = await listInflightWorkflowsAggregatedByEntity(portId, 'client', otherClient!.id);
+    expect(result.groups).toEqual([]);
+  });
 });
 
 // ─── applyEntityFkFromFolder ──────────────────────────────────────────────────