diff --git a/ChangeLog b/ChangeLog
index 0b2d36bf09..e6c63f6e3d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Thu Dec 20 09:42:11 2007  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* bignum.c (big2str_orig): access beyond memory region cause crash
+	  on interrupt.  a patch from Yusuke ENDOH <mame AT tsg.ne.jp> in 
+	  [ruby-dev:32651].  [ruby-dev:32641]
+
 Thu Dec 20 09:06:54 2007  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* string.c (rb_str_index): wrong starting position.
diff --git a/bignum.c b/bignum.c
index 8e2ae98bcd..39afad90c5 100644
--- a/bignum.c
+++ b/bignum.c
@@ -837,12 +837,12 @@ big2str_orig(VALUE x, int base, char* ptr, long len, long hbase, int trim)
         while (k--) {
             ptr[--j] = ruby_digitmap[num % base];
             num /= base;
-            if (!trim && j <= 0) break;
+            if (j <= 0) break;
             if (trim && i == 0 && num == 0) break;
         }
     }
     if (trim) {
-        while (ptr[j] == '0') j++;
+        while (j < len && ptr[j] == '0') j++;
         MEMMOVE(ptr, ptr + j, char, len - j);
         len -= j;
     }