diff --git a/Xext/geext.c b/Xext/geext.c
index b37c1a0bd..a6fbb0947 100644
--- a/Xext/geext.c
+++ b/Xext/geext.c
@@ -185,7 +185,7 @@ SGEGenericEvent(xEvent* from, xEvent* to)
     xGenericEvent* gefrom = (xGenericEvent*)from;
     xGenericEvent* geto = (xGenericEvent*)to;
 
-    if (gefrom->extension > MAXEXTENSIONS)
+    if ((gefrom->extension & 0x7f) > MAXEXTENSIONS)
     {
         ErrorF("GE: Invalid extension offset for event.\n");
         return;