diff --git a/src/app/api/v1/admin/invitations/[id]/resend/route.ts b/src/app/api/v1/admin/invitations/[id]/resend/route.ts
index cd22300..da39a76 100644
--- a/src/app/api/v1/admin/invitations/[id]/resend/route.ts
+++ b/src/app/api/v1/admin/invitations/[id]/resend/route.ts
@@ -1,12 +1,18 @@
 import { NextResponse } from 'next/server';
 
 import { withAuth, withPermission } from '@/lib/api/helpers';
-import { errorResponse } from '@/lib/errors';
+import { errorResponse, ForbiddenError } from '@/lib/errors';
 import { resendCrmInvite } from '@/lib/services/crm-invite.service';
 
+// Resend mints a fresh token + new email on a global invite row;
+// restrict to super-admins to match revoke/list and avoid cross-tenant
+// re-issuance of foreign-port invitations.
 export const POST = withAuth(
   withPermission('admin', 'manage_users', async (_req, ctx, params) => {
     try {
+      if (!ctx.isSuperAdmin) {
+        throw new ForbiddenError('Resending CRM invites requires super-admin');
+      }
       const id = params.id ?? '';
       const result = await resendCrmInvite(id, {
         userId: ctx.userId,
diff --git a/src/app/api/v1/admin/invitations/[id]/route.ts b/src/app/api/v1/admin/invitations/[id]/route.ts
index e8aac2d..05f838e 100644
--- a/src/app/api/v1/admin/invitations/[id]/route.ts
+++ b/src/app/api/v1/admin/invitations/[id]/route.ts
@@ -1,12 +1,18 @@
 import { NextResponse } from 'next/server';
 
 import { withAuth, withPermission } from '@/lib/api/helpers';
-import { errorResponse } from '@/lib/errors';
+import { errorResponse, ForbiddenError } from '@/lib/errors';
 import { revokeCrmInvite } from '@/lib/services/crm-invite.service';
 
+// Invites are a global resource (no portId column). Revoking a foreign
+// tenant's pending invite by id would be cross-tenant tampering;
+// restrict to super-admins to match the listing endpoint.
 export const DELETE = withAuth(
   withPermission('admin', 'manage_users', async (_req, ctx, params) => {
     try {
+      if (!ctx.isSuperAdmin) {
+        throw new ForbiddenError('Revoking CRM invites requires super-admin');
+      }
       const id = params.id ?? '';
       await revokeCrmInvite(id, {
         userId: ctx.userId,
diff --git a/src/app/api/v1/admin/invitations/route.ts b/src/app/api/v1/admin/invitations/route.ts
index 6cfbdde..acfbbfb 100644
--- a/src/app/api/v1/admin/invitations/route.ts
+++ b/src/app/api/v1/admin/invitations/route.ts
@@ -7,8 +7,16 @@ import { errorResponse, ForbiddenError } from '@/lib/errors';
 import { createCrmInvite, listCrmInvites } from '@/lib/services/crm-invite.service';
 
 export const GET = withAuth(
-  withPermission('admin', 'manage_users', async (_req, _ctx) => {
+  withPermission('admin', 'manage_users', async (_req, ctx) => {
     try {
+      // crm_user_invites is a global table (no per-port column) — invites
+      // mint better-auth users that may later be assigned roles in any
+      // port. Listing it cross-tenant would let a port-A director
+      // enumerate pending invitee emails, names, and isSuperAdmin flags
+      // for every other tenant. Restrict the listing to super-admins.
+      if (!ctx.isSuperAdmin) {
+        throw new ForbiddenError('Listing CRM invites requires super-admin');
+      }
       const data = await listCrmInvites();
       return NextResponse.json({ data });
     } catch (error) {
diff --git a/src/lib/socket/server.ts b/src/lib/socket/server.ts
index 1fd115b..d4b8b92 100644
--- a/src/lib/socket/server.ts
+++ b/src/lib/socket/server.ts
@@ -1,15 +1,75 @@
 import { Server } from 'socket.io';
 import { createAdapter } from '@socket.io/redis-adapter';
 import type { Server as HTTPServer } from 'node:http';
+import { and, eq } from 'drizzle-orm';
 
 import { redis } from '@/lib/redis';
 import { auth } from '@/lib/auth';
+import { db } from '@/lib/db';
+import { userProfiles, userPortRoles } from '@/lib/db/schema/users';
+import { berths } from '@/lib/db/schema/berths';
+import { clients } from '@/lib/db/schema/clients';
+import { interests } from '@/lib/db/schema/interests';
 import { logger } from '@/lib/logger';
 import type { ServerToClientEvents, ClientToServerEvents } from './events';
 
 let io: Server<ClientToServerEvents, ServerToClientEvents> | null = null;
 
-export function initSocketServer(httpServer: HTTPServer): Server<ClientToServerEvents, ServerToClientEvents> {
+/**
+ * Returns true if the user is a super-admin OR holds a userPortRoles row
+ * for the given portId. The Socket.IO auth middleware uses this to decide
+ * whether to honour a client-supplied `auth.portId` — the prior code
+ * trusted whatever the client passed and thereby joined the socket to a
+ * foreign tenant's broadcast room.
+ */
+async function userCanAccessPort(userId: string, portId: string): Promise<boolean> {
+  const profile = await db.query.userProfiles.findFirst({
+    where: eq(userProfiles.userId, userId),
+  });
+  if (profile?.isSuperAdmin) return true;
+  const role = await db.query.userPortRoles.findFirst({
+    where: and(eq(userPortRoles.userId, userId), eq(userPortRoles.portId, portId)),
+  });
+  return Boolean(role);
+}
+
+/**
+ * Verify the user can join an entity-scoped room. Each entity type's own
+ * tenant column is checked — if the user can access the entity's port,
+ * they may subscribe to that entity's room.
+ */
+async function userCanJoinEntity(
+  userId: string,
+  type: 'berth' | 'client' | 'interest',
+  id: string,
+): Promise<boolean> {
+  const profile = await db.query.userProfiles.findFirst({
+    where: eq(userProfiles.userId, userId),
+  });
+  if (profile?.isSuperAdmin) return true;
+
+  let entityPortId: string | null = null;
+  if (type === 'berth') {
+    const row = await db.query.berths.findFirst({ where: eq(berths.id, id) });
+    entityPortId = row?.portId ?? null;
+  } else if (type === 'client') {
+    const row = await db.query.clients.findFirst({ where: eq(clients.id, id) });
+    entityPortId = row?.portId ?? null;
+  } else if (type === 'interest') {
+    const row = await db.query.interests.findFirst({ where: eq(interests.id, id) });
+    entityPortId = row?.portId ?? null;
+  }
+  if (!entityPortId) return false;
+
+  const role = await db.query.userPortRoles.findFirst({
+    where: and(eq(userPortRoles.userId, userId), eq(userPortRoles.portId, entityPortId)),
+  });
+  return Boolean(role);
+}
+
+export function initSocketServer(
+  httpServer: HTTPServer,
+): Server<ClientToServerEvents, ServerToClientEvents> {
   const pubClient = redis.duplicate();
   const subClient = redis.duplicate();
 
@@ -24,7 +84,10 @@ export function initSocketServer(httpServer: HTTPServer): Server<ClientToServerE
     maxHttpBufferSize: 1e6, // 1MB message limit
   });
 
-  // Auth middleware — validate session cookie via Better Auth
+  // Auth middleware — validate session cookie + verify the user actually
+  // holds a role in the requested port. The handshake's auth.portId is
+  // user-supplied; we MUST cross-check it against userPortRoles or any
+  // authenticated user could subscribe to a foreign tenant's broadcasts.
   io.use(async (socket, next) => {
     try {
       const cookie = socket.handshake.headers.cookie;
@@ -42,9 +105,17 @@ export function initSocketServer(httpServer: HTTPServer): Server<ClientToServerE
         return next(new Error('Maximum connections reached'));
       }
 
+      const requestedPortId = socket.handshake.auth.portId as string | undefined;
+      if (requestedPortId) {
+        const allowed = await userCanAccessPort(session.user.id, requestedPortId);
+        if (!allowed) {
+          return next(new Error('No access to this port'));
+        }
+      }
+
       socket.data = {
         userId: session.user.id,
-        portId: socket.handshake.auth.portId as string | undefined,
+        portId: requestedPortId,
       };
       next();
     } catch {
@@ -61,9 +132,18 @@ export function initSocketServer(httpServer: HTTPServer): Server<ClientToServerE
     socket.join(`user:${userId}`);
     if (portId) socket.join(`port:${portId}`);
 
-    // Entity-level room management
-    socket.on('join:entity', ({ type, id }) => {
-      socket.join(`${type}:${id}`);
+    // Entity-level room management — verify the user can access the
+    // entity's port before joining. Without this, any authenticated user
+    // could subscribe to a foreign-tenant entity's broadcast (note
+    // previews, signer emails, etc.) by guessing or harvesting an id.
+    socket.on('join:entity', async ({ type, id }) => {
+      try {
+        const ok = await userCanJoinEntity(userId, type, id);
+        if (ok) socket.join(`${type}:${id}`);
+        else logger.warn({ userId, type, id }, 'Socket denied join:entity');
+      } catch (err) {
+        logger.warn({ err, userId, type, id }, 'join:entity check failed');
+      }
     });
     socket.on('leave:entity', ({ type, id }) => {
       socket.leave(`${type}:${id}`);