--- a/dom/media/MediaManager.cpp
+++ b/dom/media/MediaManager.cpp
@@ -3138,16 +3138,21 @@ MediaManager::OnNavigation(uint64_t aWin
   if (window) {
     IterateWindowListeners(window->AsInner(), StopSharingCallback, nullptr);
   } else {
     RemoveWindowID(aWindowID);
   }
   MOZ_ASSERT(!GetWindowListener(aWindowID));
 
   RemoveMediaDevicesCallback(aWindowID);
+
+  RefPtr<MediaManager> self = this;
+  MediaManager::PostTask(NewTaskFrom([self, aWindowID]() {
+    self->GetBackend()->ReleaseResourcesForWindow(aWindowID);
+  }));
 }
 
 void
 MediaManager::RemoveMediaDevicesCallback(uint64_t aWindowID)
 {
   MutexAutoLock lock(mCallbackMutex);
   for (DeviceChangeCallback* observer : mDeviceChangeCallbackList)
   {