diff --git a/src/core/peg.c b/src/core/peg.c
index 0a2b7d4f..f2e70213 100644
--- a/src/core/peg.c
+++ b/src/core/peg.c
@@ -498,6 +498,7 @@ tail:
 
         case RULE_NTH: {
             uint32_t nth = rule[1];
+            if (nth > INT32_MAX) nth = INT32_MAX;
             uint32_t tag = rule[3];
             int oldmode = s->mode;
             CapState cs = cap_save(s);