Index: krb5-1.8.1/src/lib/gssapi/krb5/accept_sec_context.c
===================================================================
--- krb5-1.8.1.orig/src/lib/gssapi/krb5/accept_sec_context.c
+++ krb5-1.8.1/src/lib/gssapi/krb5/accept_sec_context.c
@@ -647,6 +647,13 @@ kg_accept_krb5(minor_status, context_han
             goto fail;
         }
 
+        if (authdat->checksum == NULL) {
+	   /* missing checksum counts as "inappropriate type" */
+	   code = KRB5KRB_AP_ERR_INAPP_CKSUM;
+	   major_status = GSS_S_FAILURE;
+	   goto fail;
+	}
+
         /* verify that the checksum is correct */
 
         /*