1 files changed, 1 insertions, 1 deletions
diff --git a/src/string.c b/src/string.c
index bf11ed668..e61a85cff 100644
--- a/src/string.c
+++ b/src/string.c
@@ -2500,7 +2500,7 @@ mrb_str_len_to_dbl(mrb_state *mrb, const char *s, size_t len, mrb_bool badcheck)
   double d;
 
   if (!p) return 0.0;
-  while (ISSPACE(*p)) p++;
+  while (p<pend && ISSPACE(*p)) p++;
 
   if (pend - p > 2 && p[0] == '0' && (p[1] == 'x' || p[1] == 'X')) {
     mrb_value x;