--- a/dom/ipc/ContentParent.cpp
+++ b/dom/ipc/ContentParent.cpp
@@ -4403,16 +4403,20 @@ ContentParent::NotifyUpdatedFonts()
 ContentParent::UnregisterRemoteFrame(const TabId& aTabId,
                                const ContentParentId& aCpId,
                                bool aMarkedDestroying)
 {
   if (XRE_IsParentProcess()) {
     ContentProcessManager* cpm = ContentProcessManager::GetSingleton();
     ContentParent* cp = cpm->GetContentProcessById(aCpId);
 
+    if (!cp) {
+      return;
+    }
+
     cp->NotifyTabDestroyed(aTabId, aMarkedDestroying);
 
     ContentProcessManager::GetSingleton()->UnregisterRemoteFrame(aCpId, aTabId);
   } else {
     ContentChild::GetSingleton()->SendUnregisterRemoteFrame(aTabId, aCpId,
                                                       aMarkedDestroying);
   }
 }