diff --git a/src/regexp_nfa.c b/src/regexp_nfa.c
index 5ba80f2..804d742 100644
--- a/src/regexp_nfa.c
+++ b/src/regexp_nfa.c
@@ -1446,8 +1446,14 @@
 	case Magic('7'):
 	case Magic('8'):
 	case Magic('9'):
-	    EMIT(NFA_BACKREF1 + (no_Magic(c) - '1'));
-	    nfa_has_backref = TRUE;
+	    {
+		int refnum = no_Magic(c) - '1';
+
+		if (!seen_endbrace(refnum + 1))
+		    return FAIL;
+		EMIT(NFA_BACKREF1 + refnum);
+		nfa_has_backref = TRUE;
+	    }
 	    break;
 
 	case Magic('z'):