diff --git a/dom/security/nsCSPService.cpp b/dom/security/nsCSPService.cpp
index bd8dfbfbd88d..d749daebd72f 100644
--- a/dom/security/nsCSPService.cpp
+++ b/dom/security/nsCSPService.cpp
@@ -296,12 +296,13 @@ CSPService::AsyncOnChannelRedirect(nsIChannel* oldChannel,
     return rv;
   }
 
-  int16_t decision = nsIContentPolicy::ACCEPT;
-  rv = ConsultCSPForRedirect(originalUri, newUri, loadInfo, &decision);
-  if (NS_CP_REJECTED(decision)) {
+  Maybe<nsresult> cancelCode;
+  rv = ConsultCSPForRedirect(originalUri, newUri, loadInfo, cancelCode);
+  if (cancelCode) {
+    oldChannel->Cancel(*cancelCode);
+  }
+  if (NS_FAILED(rv)) {
     autoCallback.DontCallback();
-    oldChannel->Cancel(NS_ERROR_DOM_BAD_URI);
-    return NS_BINDING_FAILED;
   }
 
   return rv;
@@ -310,15 +311,15 @@ CSPService::AsyncOnChannelRedirect(nsIChannel* oldChannel,
 nsresult CSPService::ConsultCSPForRedirect(nsIURI* aOriginalURI,
                                            nsIURI* aNewURI,
                                            nsILoadInfo* aLoadInfo,
-                                           int16_t* aDecision) {
+                                           Maybe<nsresult>& aCancelCode) {
   nsCOMPtr<nsICSPEventListener> cspEventListener;
   nsresult rv =
       aLoadInfo->GetCspEventListener(getter_AddRefs(cspEventListener));
-  NS_ENSURE_SUCCESS(rv, rv);
+  MOZ_ALWAYS_SUCCEEDS(rv);
 
   nsAutoString cspNonce;
   rv = aLoadInfo->GetCspNonce(cspNonce);
-  NS_ENSURE_SUCCESS(rv, rv);
+  MOZ_ALWAYS_SUCCEEDS(rv);
 
   nsContentPolicyType policyType = aLoadInfo->InternalContentPolicyType();
   bool isPreload = nsContentUtils::IsPreloadType(policyType);
@@ -330,6 +331,7 @@ nsresult CSPService::ConsultCSPForRedirect(nsIURI* aOriginalURI,
   policyType =
       nsContentUtils::InternalContentPolicyTypeToExternalOrWorker(policyType);
 
+  int16_t decision = nsIContentPolicy::ACCEPT;
   nsCOMPtr<nsISupports> requestContext = aLoadInfo->GetLoadingContext();
   // 1) Apply speculative CSP for preloads
   if (isPreload) {
@@ -346,12 +348,13 @@ nsresult CSPService::ConsultCSPForRedirect(nsIURI* aOriginalURI,
           aOriginalURI,    // Original nsIURI
           true,            // aSendViolationReports
           cspNonce,        // nonce
-          aDecision);
+          &decision);
 
       // if the preload policy already denied the load, then there
       // is no point in checking the real policy
-      if (NS_CP_REJECTED(*aDecision)) {
-        return NS_OK;
+      if (NS_CP_REJECTED(decision)) {
+        aCancelCode = Some(NS_ERROR_DOM_BAD_URI);
+        return NS_BINDING_FAILED;
       }
     }
   }
@@ -369,7 +372,11 @@ nsresult CSPService::ConsultCSPForRedirect(nsIURI* aOriginalURI,
                     aOriginalURI,    // Original nsIURI
                     true,            // aSendViolationReports
                     cspNonce,        // nonce
-                    aDecision);
+                    &decision);
+    if (NS_CP_REJECTED(decision)) {
+      aCancelCode = Some(NS_ERROR_DOM_BAD_URI);
+      return NS_BINDING_FAILED;
+    }
   }
 
   return NS_OK;
diff --git a/dom/security/nsCSPService.h b/dom/security/nsCSPService.h
index a90627a61ce3..b94e1f421557 100644
--- a/dom/security/nsCSPService.h
+++ b/dom/security/nsCSPService.h
@@ -34,9 +34,13 @@ class CSPService : public nsIContentPolicy, public nsIChannelEventSink {
                              const nsACString& aMimeTypeGuess,
                              int16_t* aDecision);
 
+  // Static helper to check CSP when doing a channel redirect.
+  // Returns the results to returns from
+  // AsyncOnChannelRedirect/nsIAsyncVerifyRedirectCallback. Optionally returns
+  // an nsresult to Cancel the old channel with.
   static nsresult ConsultCSPForRedirect(nsIURI* aOriginalURI, nsIURI* aNewURI,
                                         nsILoadInfo* aLoadInfo,
-                                        int16_t* aDecision);
+                                        Maybe<nsresult>& aCancelCode);
 
  protected:
   virtual ~CSPService();
diff --git a/netwerk/ipc/DocumentChannelChild.cpp b/netwerk/ipc/DocumentChannelChild.cpp
index 1889933b0952..eaea8faa73be 100644
--- a/netwerk/ipc/DocumentChannelChild.cpp
+++ b/netwerk/ipc/DocumentChannelChild.cpp
@@ -412,22 +412,15 @@ IPCResult DocumentChannelChild::RecvConfirmRedirect(
   nsCOMPtr<nsIURI> originalUri;
   nsresult rv = GetOriginalURI(getter_AddRefs(originalUri));
   if (NS_FAILED(rv)) {
-    aResolve(rv);
+    aResolve(Tuple<const nsresult&, const Maybe<nsresult>&>(NS_BINDING_FAILED,
+                                                            Some(rv)));
     return IPC_OK();
   }
 
-  int16_t decision = nsIContentPolicy::ACCEPT;
+  Maybe<nsresult> cancelCode;
   rv = CSPService::ConsultCSPForRedirect(originalUri, aNewUri, mLoadInfo,
-                                         &decision);
-  if (NS_FAILED(rv)) {
-    aResolve(rv);
-    return IPC_OK();
-  }
-  if (NS_CP_REJECTED(decision)) {
-    aResolve(NS_BINDING_FAILED);
-  } else {
-    aResolve(NS_OK);
-  }
+                                         cancelCode);
+  aResolve(Tuple<const nsresult&, const Maybe<nsresult>&>(rv, cancelCode));
   return IPC_OK();
 }
 
diff --git a/netwerk/ipc/DocumentChannelParent.cpp b/netwerk/ipc/DocumentChannelParent.cpp
index b6b7092a4b69..720450d2ef2c 100644
--- a/netwerk/ipc/DocumentChannelParent.cpp
+++ b/netwerk/ipc/DocumentChannelParent.cpp
@@ -240,8 +240,8 @@ void DocumentChannelParent::FinishReplacementChannelSetup(bool aSucceeded) {
         newChannel->Cancel(NS_BINDING_ABORTED);
       }
     }
-    // Release all previously registered channels, they are no longer needed to be
-    // kept in the registrar from this moment.
+    // Release all previously registered channels, they are no longer needed to
+    // be kept in the registrar from this moment.
     registrar->DeregisterChannels(mRedirectChannelId);
 
     mRedirectChannelId = 0;
@@ -809,11 +809,11 @@ DocumentChannelParent::AsyncOnChannelRedirect(
   nsCOMPtr<nsIChannel> oldChannel(aOldChannel);
   SendConfirmRedirect(newUri)->Then(
       GetCurrentThreadSerialEventTarget(), __func__,
-      [callback, oldChannel](nsresult aRv) {
-        if (NS_FAILED(aRv)) {
-          oldChannel->Cancel(NS_ERROR_DOM_BAD_URI);
+      [callback, oldChannel](const Tuple<nsresult, Maybe<nsresult>>& aResult) {
+        if (Get<1>(aResult)) {
+          oldChannel->Cancel(*Get<1>(aResult));
         }
-        callback->OnRedirectVerifyCallback(aRv);
+        callback->OnRedirectVerifyCallback(Get<0>(aResult));
       },
       [callback, oldChannel](const mozilla::ipc::ResponseRejectReason) {
         oldChannel->Cancel(NS_ERROR_DOM_BAD_URI);
diff --git a/netwerk/ipc/PDocumentChannel.ipdl b/netwerk/ipc/PDocumentChannel.ipdl
index 5491cd944fcf..86a725b96fb0 100644
--- a/netwerk/ipc/PDocumentChannel.ipdl
+++ b/netwerk/ipc/PDocumentChannel.ipdl
@@ -75,7 +75,7 @@ child:
                               uint32_t? aContentDisposition,
                               nsString? aContentDispositionFilename) returns(nsresult rv);
 
-  async ConfirmRedirect(nsIURI aNewURI) returns(nsresult rv);
+  async ConfirmRedirect(nsIURI aNewURI) returns(nsresult rv, nsresult? cancelCode);
 
   // Tell child to delete channel (all IPDL deletes must be done from child to
   // avoid races: see bug 591708).