diff --git a/docshell/base/nsDocShell.cpp b/docshell/base/nsDocShell.cpp
index 3234bfaab92f..3c69180a3263 100644
--- a/docshell/base/nsDocShell.cpp
+++ b/docshell/base/nsDocShell.cpp
@@ -22,6 +22,7 @@
 #include "mozilla/Telemetry.h"
 #include "mozilla/unused.h"
 #include "mozilla/VisualEventTracer.h"
+#include "URIUtils.h"
 
 #ifdef MOZ_LOGGING
 // so we can get logging even in release builds (but only for some things)
@@ -4559,16 +4560,24 @@ nsDocShell::DisplayLoadError(nsresult aError, nsIURI *aURI,
 
                 // if this is a Strict-Transport-Security host and the cert
                 // is bad, don't allow overrides (STS Spec section 7.3).
-                nsCOMPtr<nsISiteSecurityService> sss =
-                          do_GetService(NS_SSSERVICE_CONTRACTID, &rv);
-                NS_ENSURE_SUCCESS(rv, rv);
-                uint32_t flags =
-                  mInPrivateBrowsing ? nsISocketProvider::NO_PERMANENT_STORAGE : 0;
-                
+                uint32_t type = nsISiteSecurityService::HEADER_HSTS;
+                uint32_t flags = mInPrivateBrowsing
+                                 ? nsISocketProvider::NO_PERMANENT_STORAGE
+                                 : 0;
                 bool isStsHost = false;
-                rv = sss->IsSecureURI(nsISiteSecurityService::HEADER_HSTS,
-                                      aURI, flags, &isStsHost);
-                NS_ENSURE_SUCCESS(rv, rv);
+                if (XRE_GetProcessType() == GeckoProcessType_Default) {
+                  nsCOMPtr<nsISiteSecurityService> sss =
+                            do_GetService(NS_SSSERVICE_CONTRACTID, &rv);
+                  NS_ENSURE_SUCCESS(rv, rv);
+                  rv = sss->IsSecureURI(type, aURI, flags, &isStsHost);
+                  NS_ENSURE_SUCCESS(rv, rv);
+                } else {
+                  mozilla::dom::ContentChild* cc =
+                    mozilla::dom::ContentChild::GetSingleton();
+                  mozilla::ipc::URIParams uri;
+                  SerializeURI(aURI, uri);
+                  cc->SendIsSecureURI(type, uri, flags, &isStsHost);
+                }
 
                 uint32_t bucketId;
                 if (isStsHost) {
diff --git a/dom/ipc/ContentParent.cpp b/dom/ipc/ContentParent.cpp
index 1a0fd0facdbd..3dfe0bf6d73c 100644
--- a/dom/ipc/ContentParent.cpp
+++ b/dom/ipc/ContentParent.cpp
@@ -98,6 +98,7 @@
 #include "nsIPresShell.h"
 #include "nsIRemoteBlob.h"
 #include "nsIScriptError.h"
+#include "nsISiteSecurityService.h"
 #include "nsIStyleSheet.h"
 #include "nsISupportsPrimitives.h"
 #include "nsIURIFixup.h"
@@ -3239,6 +3240,23 @@ ContentParent::RecvGetSystemMemory(const uint64_t& aGetterId)
     return true;
 }
 
+bool
+ContentParent::RecvIsSecureURI(const uint32_t& type,
+                               const URIParams& uri,
+                               const uint32_t& flags,
+                               bool* isSecureURI)
+{
+    nsCOMPtr<nsISiteSecurityService> sss(do_GetService(NS_SSSERVICE_CONTRACTID));
+    if (!sss) {
+        return false;
+    }
+    nsCOMPtr<nsIURI> ourURI = DeserializeURI(uri);
+    if (!ourURI) {
+        return false;
+    }
+    nsresult rv = sss->IsSecureURI(type, ourURI, flags, isSecureURI);
+    return NS_SUCCEEDED(rv);
+}
 
 bool
 ContentParent::RecvLoadURIExternal(const URIParams& uri)
diff --git a/dom/ipc/ContentParent.h b/dom/ipc/ContentParent.h
index f2546c1b8445..f29895120cf7 100644
--- a/dom/ipc/ContentParent.h
+++ b/dom/ipc/ContentParent.h
@@ -422,6 +422,9 @@ private:
     virtual bool RecvGetRandomValues(const uint32_t& length,
                                      InfallibleTArray<uint8_t>* randomValues) MOZ_OVERRIDE;
 
+    virtual bool RecvIsSecureURI(const uint32_t& type, const URIParams& uri,
+                                 const uint32_t& flags, bool* isSecureURI);
+
     virtual bool DeallocPHalParent(PHalParent*) MOZ_OVERRIDE;
 
     virtual bool DeallocPIndexedDBParent(PIndexedDBParent* aActor) MOZ_OVERRIDE;
diff --git a/dom/ipc/PContent.ipdl b/dom/ipc/PContent.ipdl
index 3f6a86529a4e..e3581bec1a34 100644
--- a/dom/ipc/PContent.ipdl
+++ b/dom/ipc/PContent.ipdl
@@ -478,6 +478,9 @@ parent:
 
     async GetSystemMemory(uint64_t getterId);
 
+    sync IsSecureURI(uint32_t type, URIParams uri, uint32_t flags)
+        returns (bool isSecureURI);
+
     PHal();
 
     PIndexedDB();
diff --git a/security/manager/boot/src/nsSiteSecurityService.cpp b/security/manager/boot/src/nsSiteSecurityService.cpp
index 3cab048ec8f6..30cc0de889bd 100644
--- a/security/manager/boot/src/nsSiteSecurityService.cpp
+++ b/security/manager/boot/src/nsSiteSecurityService.cpp
@@ -20,6 +20,7 @@
 #include "mozilla/Preferences.h"
 #include "mozilla/LinkedList.h"
 #include "nsSecurityHeaderParser.h"
+#include "nsXULAppAPI.h"
 
 // A note about the preload list:
 // When a site specifically disables sts by sending a header with
@@ -87,6 +88,11 @@ NS_IMPL_ISUPPORTS(nsSiteSecurityService,
 nsresult
 nsSiteSecurityService::Init()
 {
+   // Child processes are not allowed direct access to this.
+   if (XRE_GetProcessType() != GeckoProcessType_Default) {
+     MOZ_CRASH("Child process: no direct access to nsSiteSecurityService");
+   }
+
    nsresult rv;
 
    mPermMgr = do_GetService(NS_PERMISSIONMANAGER_CONTRACTID, &rv);