diff --git a/src/lib/common/xundump.c b/src/lib/common/xundump.c
index 4f1ad999..54448f64 100644
--- a/src/lib/common/xundump.c
+++ b/src/lib/common/xundump.c
@@ -352,7 +352,7 @@ deffld(int fldno, char *name, int idx)
     if (res < 0)
 	return gripe("Header %s of field %d is %s", name, fldno + 1,
 		     res == M_NOTUNIQUE ? "ambiguous" : "unknown");
-    if (ca[res].ca_flags == NSC_EXTRA || CANT_HAPPEN(ca[res].ca_get))
+    if ((ca[res].ca_flags & NSC_EXTRA) || CANT_HAPPEN(ca[res].ca_get))
 	return gripe("Extraneous header %s in field %d", name, fldno + 1);
     if (ca[res].ca_type != NSC_STRINGY && ca[res].ca_len != 0) {
 	if (idx < 0)