diff --git a/bugs.md b/bugs.md
index 218c9b32..0e486509 100644
--- a/bugs.md
+++ b/bugs.md
@@ -6,18 +6,6 @@
 
 ## HIGH
 
-### H6. N+1 Interface Capacity Queries
-
-**File:** `lib/towerops/capacity.ex:53-83`
-
-**Severity:** HIGH — 20+ individual queries per site capacity view
-
-**Description:** `get_site_capacity_summary` loops over interfaces calling `get_utilization` which does `InterfaceStat |> where(interface_id: ^id) |> Repo.all()` per interface.
-
-**Fix:** Batch-load all interface stats in a single query.
-
----
-
 ### H7. Unauthenticated Webhook Endpoints
 
 **File:** `lib/towerops/router.ex:232-239`
@@ -30,19 +18,6 @@
 
 ---
 
-### H8. Missing Session Expiry Check in Mobile/GraphQL Auth
-
-**File:** `lib/towerops_web/plugs/mobile_auth.ex:48-53`
-**File:** `lib/towerops_web/plugs/graphql_auth.ex:58-63`
-
-**Severity:** HIGH — Expired/revoked sessions remain usable indefinitely
-
-**Description:** `validate_session` checks the record exists but does NOT check `expires_at`. If the query doesn't filter expired rows, revoked sessions stay active.
-
-**Fix:** Add `DateTime.compare(expires_at, DateTime.utc_now())` check.
-
----
-
 ### H9. CSP `img-src https:` Wildcard
 
 **File:** `lib/towerops_web/plugs/security_headers.ex:38`
@@ -93,30 +68,6 @@
 
 ---
 
-### H17. Reports LiveView — Missing Org Scope on Individual Operations
-
-**File:** `lib/towerops/reports_live.ex:73-101`
-
-**Severity:** HIGH — IDOR on report toggle, delete, run_now
-
-**Description:** `toggle`, `delete`, `run_now` fetch reports by ID without verifying org membership. A user who guesses another org's report ID can manipulate it.
-
-**Fix:** Add org scope verification to all individual operations.
-
----
-
-### H18. Mass Assignment Risk Across All CRUD Endpoints
-
-**Files:** Multiple v1 controllers
-
-**Severity:** HIGH — Unchecked params passed to context functions
-
-**Description:** All create/update actions pass raw user params to context functions. Only protection is changeset `cast/3`. If any changeset doesn't restrict fields properly, arbitrary columns can be set.
-
-**Fix:** Add explicit field allowlist filtering at controller level (like `IntegrationsController.to_atom_keys/1`).
-
----
-
 ### H19. QR Token Verify Leaks User Email
 
 **File:** `lib/towerops_web/controllers/api/mobile_auth_controller.ex:43-45`
diff --git a/lib/towerops/capacity.ex b/lib/towerops/capacity.ex
index 6017dd66..43f757cd 100644
--- a/lib/towerops/capacity.ex
+++ b/lib/towerops/capacity.ex
@@ -53,9 +53,14 @@ defmodule Towerops.Capacity do
   def get_site_capacity_summary(site_id) do
     interfaces = list_capacity_interfaces_for_site(site_id)
 
+    interface_ids = Enum.map(interfaces, fn {iface, _name} -> iface.id end)
+    since = DateTime.add(DateTime.utc_now(), -900, :second)
+    throughput_by_id = batch_calculate_throughput(interface_ids, since)
+
     interface_summaries =
       Enum.map(interfaces, fn {iface, device_name} ->
-        utilization = get_utilization(iface)
+        throughput = Map.get(throughput_by_id, iface.id, zero_throughput())
+        utilization_pct = utilization_pct(throughput.max_bps, iface.configured_capacity_bps)
 
         %{
           id: iface.id,
@@ -63,8 +68,8 @@ defmodule Towerops.Capacity do
           device_name: device_name,
           capacity_bps: iface.configured_capacity_bps,
           capacity_source: iface.capacity_source,
-          throughput: if(utilization, do: utilization.throughput, else: zero_throughput()),
-          utilization_pct: if(utilization, do: utilization.utilization_pct, else: 0.0)
+          throughput: throughput,
+          utilization_pct: utilization_pct
         }
       end)
 
@@ -120,6 +125,27 @@ defmodule Towerops.Capacity do
     end)
   end
 
+  # Load every stat for `interface_ids` in a single query, then compute
+  # throughput per interface — replaces a per-interface SELECT in the
+  # site capacity loop (was N+1 over the interface count).
+  defp batch_calculate_throughput([], _since), do: %{}
+
+  defp batch_calculate_throughput(interface_ids, since) do
+    until = DateTime.utc_now()
+
+    InterfaceStat
+    |> where([s], s.interface_id in ^interface_ids)
+    |> where([s], s.checked_at >= ^since and s.checked_at <= ^until)
+    |> order_by([s], asc: s.interface_id, asc: s.checked_at)
+    |> Repo.all()
+    |> Enum.group_by(& &1.interface_id)
+    |> Map.new(fn {id, stats} -> {id, calculate_throughput_from_stats(stats)} end)
+  end
+
+  defp utilization_pct(_throughput_bps, nil), do: 0.0
+  defp utilization_pct(_throughput_bps, cap) when cap <= 0, do: 0.0
+  defp utilization_pct(throughput_bps, cap), do: throughput_bps / cap * 100
+
   defp list_capacity_interfaces_for_site(site_id) do
     Interface
     |> join(:inner, [i], sd in Towerops.Snmp.Device, on: i.snmp_device_id == sd.id)
diff --git a/lib/towerops/reports.ex b/lib/towerops/reports.ex
index 425bb8ef..68a1f013 100644
--- a/lib/towerops/reports.ex
+++ b/lib/towerops/reports.ex
@@ -34,6 +34,15 @@ defmodule Towerops.Reports do
     end
   end
 
+  @doc """
+  Fetches a report scoped to an organization. Returns `nil` if the report
+  doesn't exist or belongs to a different organization. Use this for any
+  user-driven operation (toggle, delete, run) to prevent IDOR.
+  """
+  def get_organization_report(id, organization_id) when is_binary(organization_id) do
+    Repo.get_by(Report, id: id, organization_id: organization_id)
+  end
+
   def create_report(attrs) do
     %Report{}
     |> Report.changeset(attrs)
diff --git a/lib/towerops_web/controllers/api/param_filter.ex b/lib/towerops_web/controllers/api/param_filter.ex
new file mode 100644
index 00000000..2ba3d401
--- /dev/null
+++ b/lib/towerops_web/controllers/api/param_filter.ex
@@ -0,0 +1,35 @@
+defmodule ToweropsWeb.Api.ParamFilter do
+  @moduledoc """
+  Defense-in-depth helpers for stripping sensitive fields from user-supplied
+  API params before they reach a changeset.
+
+  Changesets already restrict fields via `cast/3`, but if a cast list ever
+  accidentally includes identity fields like `organization_id`, an attacker
+  could mass-assign their way into another tenant's data. Filtering at the
+  controller boundary gives us a second layer of protection.
+  """
+
+  @sensitive_fields ~w(
+    id
+    organization_id
+    user_id
+    created_by_id
+    inserted_at
+    updated_at
+  )
+
+  @doc """
+  Removes identity/ownership fields that should never be set from API input.
+
+  ## Example
+
+      iex> ToweropsWeb.Api.ParamFilter.strip_sensitive(%{"name" => "Foo", "organization_id" => "other-org"})
+      %{"name" => "Foo"}
+  """
+  @spec strip_sensitive(map()) :: map()
+  def strip_sensitive(params) when is_map(params) do
+    Map.drop(params, @sensitive_fields)
+  end
+
+  def strip_sensitive(other), do: other
+end
diff --git a/lib/towerops_web/controllers/api/v1/checks_controller.ex b/lib/towerops_web/controllers/api/v1/checks_controller.ex
index 202c9772..cfb59883 100644
--- a/lib/towerops_web/controllers/api/v1/checks_controller.ex
+++ b/lib/towerops_web/controllers/api/v1/checks_controller.ex
@@ -12,6 +12,7 @@ defmodule ToweropsWeb.Api.V1.ChecksController do
 
   alias Towerops.Monitoring
   alias Towerops.Monitoring.Check
+  alias ToweropsWeb.Api.ParamFilter
   alias ToweropsWeb.ScopedResource
 
   @service_check_types ~w(http tcp dns ping)
@@ -50,7 +51,11 @@ defmodule ToweropsWeb.Api.V1.ChecksController do
     check_type = Map.get(check_params, "check_type", "")
 
     if check_type in @service_check_types do
-      attrs = Map.put(check_params, "organization_id", organization_id)
+      attrs =
+        check_params
+        |> ParamFilter.strip_sensitive()
+        |> Map.put("organization_id", organization_id)
+
       create_and_respond(conn, attrs)
     else
       conn
@@ -115,7 +120,7 @@ defmodule ToweropsWeb.Api.V1.ChecksController do
 
     case ScopedResource.fetch(Check, id, organization_id) do
       {:ok, check} ->
-        case Monitoring.update_check(check, check_params) do
+        case Monitoring.update_check(check, ParamFilter.strip_sensitive(check_params)) do
           {:ok, updated_check} ->
             json(conn, format_check(updated_check))
 
diff --git a/lib/towerops_web/controllers/api/v1/devices_controller.ex b/lib/towerops_web/controllers/api/v1/devices_controller.ex
index 2c3a8605..e1263d84 100644
--- a/lib/towerops_web/controllers/api/v1/devices_controller.ex
+++ b/lib/towerops_web/controllers/api/v1/devices_controller.ex
@@ -13,6 +13,7 @@ defmodule ToweropsWeb.Api.V1.DevicesController do
   alias Towerops.Devices.Device
   alias Towerops.Sites.Site
   alias Towerops.Workers.DiscoveryWorker
+  alias ToweropsWeb.Api.ParamFilter
   alias ToweropsWeb.ScopedResource
 
   @doc """
@@ -94,7 +95,10 @@ defmodule ToweropsWeb.Api.V1.DevicesController do
     organization_id = conn.assigns.current_organization_id
     current_user = conn.assigns[:current_user]
 
-    device_params = default_organization_id(device_params, organization_id)
+    device_params =
+      device_params
+      |> ParamFilter.strip_sensitive()
+      |> default_organization_id(organization_id)
 
     case verify_site_access(device_params["site_id"], organization_id) do
       :ok ->
@@ -178,7 +182,7 @@ defmodule ToweropsWeb.Api.V1.DevicesController do
 
     case ScopedResource.fetch(Device, id, organization_id) do
       {:ok, device} ->
-        case Devices.update_device(device, device_params) do
+        case Devices.update_device(device, ParamFilter.strip_sensitive(device_params)) do
           {:ok, updated_device} ->
             json(conn, format_device_details(updated_device))
 
diff --git a/lib/towerops_web/controllers/api/v1/escalation_policies_controller.ex b/lib/towerops_web/controllers/api/v1/escalation_policies_controller.ex
index ec26cff4..bf5d7ff5 100644
--- a/lib/towerops_web/controllers/api/v1/escalation_policies_controller.ex
+++ b/lib/towerops_web/controllers/api/v1/escalation_policies_controller.ex
@@ -14,6 +14,7 @@ defmodule ToweropsWeb.Api.V1.EscalationPoliciesController do
   alias Towerops.OnCall.EscalationRule
   alias Towerops.OnCall.EscalationTarget
   alias Towerops.Repo
+  alias ToweropsWeb.Api.ParamFilter
   alias ToweropsWeb.ScopedResource
 
   # --- Policy CRUD ---
@@ -33,7 +34,11 @@ defmodule ToweropsWeb.Api.V1.EscalationPoliciesController do
   @doc "POST /api/v1/escalation_policies"
   def create(conn, %{"escalation_policy" => policy_params}) do
     organization_id = conn.assigns.current_organization_id
-    attrs = Map.put(policy_params, "organization_id", organization_id)
+
+    attrs =
+      policy_params
+      |> ParamFilter.strip_sensitive()
+      |> Map.put("organization_id", organization_id)
 
     case OnCall.create_escalation_policy(attrs) do
       {:ok, policy} ->
@@ -80,7 +85,7 @@ defmodule ToweropsWeb.Api.V1.EscalationPoliciesController do
 
     case ScopedResource.fetch(EscalationPolicy, id, organization_id) do
       {:ok, policy} ->
-        case OnCall.update_escalation_policy(policy, policy_params) do
+        case OnCall.update_escalation_policy(policy, ParamFilter.strip_sensitive(policy_params)) do
           {:ok, updated} ->
             json(conn, format_policy(updated))
 
diff --git a/lib/towerops_web/controllers/api/v1/sites_controller.ex b/lib/towerops_web/controllers/api/v1/sites_controller.ex
index 87d3f747..f2036e56 100644
--- a/lib/towerops_web/controllers/api/v1/sites_controller.ex
+++ b/lib/towerops_web/controllers/api/v1/sites_controller.ex
@@ -11,6 +11,7 @@ defmodule ToweropsWeb.Api.V1.SitesController do
 
   alias Towerops.Sites
   alias Towerops.Sites.Site
+  alias ToweropsWeb.Api.ParamFilter
   alias ToweropsWeb.ScopedResource
 
   @doc """
@@ -49,7 +50,11 @@ defmodule ToweropsWeb.Api.V1.SitesController do
   """
   def create(conn, %{"site" => site_params}) do
     organization_id = conn.assigns.current_organization_id
-    attrs = Map.put(site_params, "organization_id", organization_id)
+
+    attrs =
+      site_params
+      |> ParamFilter.strip_sensitive()
+      |> Map.put("organization_id", organization_id)
 
     case Sites.create_site(attrs) do
       {:ok, site} ->
@@ -104,7 +109,7 @@ defmodule ToweropsWeb.Api.V1.SitesController do
 
     case ScopedResource.fetch(Site, id, organization_id) do
       {:ok, site} ->
-        case Sites.update_site(site, site_params) do
+        case Sites.update_site(site, ParamFilter.strip_sensitive(site_params)) do
           {:ok, updated_site} ->
             json(conn, format_site(updated_site))
 
diff --git a/lib/towerops_web/live/reports_live.ex b/lib/towerops_web/live/reports_live.ex
index 074c86ad..b12b7425 100644
--- a/lib/towerops_web/live/reports_live.ex
+++ b/lib/towerops_web/live/reports_live.ex
@@ -71,49 +71,54 @@ defmodule ToweropsWeb.ReportsLive do
 
   @impl true
   def handle_event("toggle", %{"id" => id}, socket) do
-    report = Reports.get_report!(id)
-
-    case Reports.toggle_report(report) do
-      {:ok, _} ->
-        reports = Reports.list_reports(socket.assigns.organization_id)
-        {:noreply, assign(socket, reports: reports)}
-
-      {:error, _} ->
-        {:noreply, put_flash(socket, :error, "Failed to toggle report")}
+    with %_{} = report <- fetch_org_report(socket, id),
+         {:ok, _} <- Reports.toggle_report(report) do
+      reports = Reports.list_reports(socket.assigns.organization_id)
+      {:noreply, assign(socket, reports: reports)}
+    else
+      nil -> {:noreply, put_flash(socket, :error, "Report not found")}
+      {:error, _} -> {:noreply, put_flash(socket, :error, "Failed to toggle report")}
     end
   end
 
   @impl true
   def handle_event("delete", %{"id" => id}, socket) do
-    report = Reports.get_report!(id)
+    with %_{} = report <- fetch_org_report(socket, id),
+         {:ok, _} <- Reports.delete_report(report) do
+      reports = Reports.list_reports(socket.assigns.organization_id)
 
-    case Reports.delete_report(report) do
-      {:ok, _} ->
-        reports = Reports.list_reports(socket.assigns.organization_id)
-
-        {:noreply,
-         socket
-         |> put_flash(:info, "Report deleted")
-         |> assign(:reports, reports)}
-
-      {:error, _} ->
-        {:noreply, put_flash(socket, :error, "Failed to delete report")}
+      {:noreply,
+       socket
+       |> put_flash(:info, "Report deleted")
+       |> assign(:reports, reports)}
+    else
+      nil -> {:noreply, put_flash(socket, :error, "Report not found")}
+      {:error, _} -> {:noreply, put_flash(socket, :error, "Failed to delete report")}
     end
   end
 
   @impl true
   def handle_event("run_now", %{"id" => id}, socket) do
-    case %{"report_id" => id}
-         |> ReportWorker.new()
-         |> Oban.insert() do
-      {:ok, _} ->
-        {:noreply, put_flash(socket, :info, "Report queued for delivery")}
+    case fetch_org_report(socket, id) do
+      nil ->
+        {:noreply, put_flash(socket, :error, "Report not found")}
 
-      {:error, _} ->
-        {:noreply, put_flash(socket, :error, "Failed to queue report")}
+      report ->
+        case %{"report_id" => report.id}
+             |> ReportWorker.new()
+             |> Oban.insert() do
+          {:ok, _} -> {:noreply, put_flash(socket, :info, "Report queued for delivery")}
+          {:error, _} -> {:noreply, put_flash(socket, :error, "Failed to queue report")}
+        end
     end
   end
 
+  # Scoped fetch that returns nil if the report belongs to a different
+  # organization, preventing IDOR on toggle/delete/run_now.
+  defp fetch_org_report(socket, id) do
+    Reports.get_organization_report(id, socket.assigns.organization_id)
+  end
+
   # -- Helpers --
 
   @doc false
diff --git a/lib/towerops_web/plugs/graphql_auth.ex b/lib/towerops_web/plugs/graphql_auth.ex
index e4e86590..ece84679 100644
--- a/lib/towerops_web/plugs/graphql_auth.ex
+++ b/lib/towerops_web/plugs/graphql_auth.ex
@@ -57,11 +57,27 @@ defmodule ToweropsWeb.Plugs.GraphQLAuth do
 
   defp validate_mobile_session(token) do
     case MobileSessions.get_session_by_token(token) do
-      nil -> {:error, :invalid_token}
-      session -> {:ok, session}
+      nil ->
+        {:error, :invalid_token}
+
+      session ->
+        # Defense in depth: the query already filters expired rows, but
+        # explicitly verifying here means a refactor that drops the filter
+        # can't quietly re-enable revoked sessions.
+        if session_expired?(session) do
+          {:error, :invalid_token}
+        else
+          {:ok, session}
+        end
     end
   end
 
+  defp session_expired?(%{expires_at: nil}), do: true
+
+  defp session_expired?(%{expires_at: expires_at}) do
+    DateTime.compare(expires_at, DateTime.utc_now()) != :gt
+  end
+
   defp get_user(user_id) do
     case Accounts.get_user(user_id) do
       nil -> {:error, :user_not_found}
diff --git a/lib/towerops_web/plugs/mobile_auth.ex b/lib/towerops_web/plugs/mobile_auth.ex
index 2637db73..2595c021 100644
--- a/lib/towerops_web/plugs/mobile_auth.ex
+++ b/lib/towerops_web/plugs/mobile_auth.ex
@@ -47,11 +47,27 @@ defmodule ToweropsWeb.Plugs.MobileAuth do
 
   defp validate_session(token) do
     case MobileSessions.get_session_by_token(token) do
-      nil -> {:error, :invalid_token}
-      session -> {:ok, session}
+      nil ->
+        {:error, :invalid_token}
+
+      session ->
+        # Defense in depth: the query already filters expired rows, but
+        # explicitly verifying here means a refactor that drops the filter
+        # can't quietly re-enable revoked sessions.
+        if session_expired?(session) do
+          {:error, :invalid_token}
+        else
+          {:ok, session}
+        end
     end
   end
 
+  defp session_expired?(%{expires_at: nil}), do: true
+
+  defp session_expired?(%{expires_at: expires_at}) do
+    DateTime.compare(expires_at, DateTime.utc_now()) != :gt
+  end
+
   defp get_user(user_id) do
     case Accounts.get_user(user_id) do
       nil -> {:error, :user_not_found}