--- a/netwerk/protocol/about/nsAboutProtocolHandler.cpp
+++ b/netwerk/protocol/about/nsAboutProtocolHandler.cpp
@@ -84,21 +84,27 @@ nsAboutProtocolHandler::GetFlagsForURI(n
       // Swallow this and just tell the consumer the default:
       return NS_OK;
     }
     uint32_t aboutModuleFlags = 0;
     rv = aboutMod->GetURIFlags(aURI, &aboutModuleFlags);
     // This should never happen, so pass back the error:
     NS_ENSURE_SUCCESS(rv, rv);
 
-    // If marked as safe, and marked linkable, pass 'safe' flags.
-    if ((aboutModuleFlags & nsIAboutModule::URI_SAFE_FOR_UNTRUSTED_CONTENT) &&
-        (aboutModuleFlags & nsIAboutModule::MAKE_LINKABLE)) {
-        *aFlags = URI_NORELATIVE | URI_NOAUTH | URI_LOADABLE_BY_ANYONE |
-            URI_SAFE_TO_LOAD_IN_SECURE_CONTEXT;
+    // Secure (https) pages can load safe about pages without becoming
+    // mixed content.
+    if (aboutModuleFlags & nsIAboutModule::URI_SAFE_FOR_UNTRUSTED_CONTENT) {
+        *aFlags |= URI_SAFE_TO_LOAD_IN_SECURE_CONTEXT;
+        // about: pages can only be loaded by unprivileged principals
+        // if they are marked as LINKABLE
+        if (aboutModuleFlags & nsIAboutModule::MAKE_LINKABLE) {
+            // Replace URI_DANGEROUS_TO_LOAD with URI_LOADABLE_BY_ANYONE.
+            *aFlags &= ~URI_DANGEROUS_TO_LOAD;
+            *aFlags |= URI_LOADABLE_BY_ANYONE;
+        }
     }
     return NS_OK;
 }
 
 NS_IMETHODIMP
 nsAboutProtocolHandler::NewURI(const nsACString &aSpec,
                                const char *aCharset, // ignore charset info
                                nsIURI *aBaseURI,