diff --git a/lib/dns/spnego.c b/lib/dns/spnego.c
index d22b8f49f7..1aa4030015 100644
--- a/lib/dns/spnego.c
+++ b/lib/dns/spnego.c
@@ -14,7 +14,7 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: spnego.c,v 1.10 2009/01/17 23:47:43 tbox Exp $ */
+/* $Id: spnego.c,v 1.11 2009/07/20 01:55:37 marka Exp $ */
 
 /*! \file
  * \brief
@@ -622,7 +622,7 @@ gss_accept_sec_context_spnego(OM_uint32 *minor_status,
 	}
 
 	for (i = 0; !found && i < init_token.mechTypes.len; ++i) {
-		char mechbuf[17];
+		unsigned char mechbuf[17];
 		size_t mech_len;
 
 		ret = der_put_oid(mechbuf + sizeof(mechbuf) - 1,