diff --git a/ChangeLog b/ChangeLog
index 324f59aea..eb03ab973 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -9,6 +9,10 @@
 	(To those wondering about the date: Yes, this is me doing an Xprint
 	commit, but it fixes the --disable-xprint path, so.)
 
+	* xkb/xkb.c: (XkbSizeVirtualModMap):
+	Bug #6428: Fix off-by-one error when walking off the end of the
+	vmodmap list.
+
 2006-03-31  Eric Anholt  <anholt@FreeBSD.org>
 
 	* exa/exa_unaccel.c: (ExaCheckComposite):
diff --git a/xkb/xkb.c b/xkb/xkb.c
index 3cdf4d124..fdfd2f3cd 100644
--- a/xkb/xkb.c
+++ b/xkb/xkb.c
@@ -1255,7 +1255,7 @@ XkbSizeVirtualModMap(XkbDescPtr xkb,xkbGetMapReply *rep)
 	rep->totalVModMapKeys= 0;
 	return 0;
     }
-    for (nRtrn=i=0;i<rep->nVModMapKeys;i++) {
+    for (nRtrn=i=0;i<rep->nVModMapKeys-1;i++) {
 	if (xkb->server->vmodmap[i+rep->firstVModMapKey]!=0)
 	    nRtrn++;
     }