diff --git a/ChangeLog b/ChangeLog
index b27f63505b..a3164ac37e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Sun Apr 28 22:04:37 2013  Hiroshi Shirosaki  <h.shirosaki@gmail.com>
+
+	* ext/openssl/ossl_bn.c (ossl_bn_initialize): fix buffer overflow on
+	  x64 Windows and memory leak when initializing with integer.
+	  [ruby-core:54615] [Bug #8337]
+
 Sun Apr 28 12:38:04 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* README.EXT: correct method name to be used.  [Bug #7982]
diff --git a/ext/openssl/ossl_bn.c b/ext/openssl/ossl_bn.c
index 4e9734ee22..7d5c7d6347 100644
--- a/ext/openssl/ossl_bn.c
+++ b/ext/openssl/ossl_bn.c
@@ -123,11 +123,11 @@ ossl_bn_initialize(int argc, VALUE *argv, VALUE self)
 
     if (RB_TYPE_P(str, T_FIXNUM)) {
 	long i;
-	unsigned char *bin = (unsigned char*)ALLOC_N(long, 1);
+	unsigned char *bin = (unsigned char*)ALLOCA_N(long, 1);
 	long n = FIX2LONG(str);
 	unsigned long un = labs(n);
 
-	for (i = sizeof(VALUE) - 1; 0 <= i; i--) {
+	for (i = sizeof(long) - 1; 0 <= i; i--) {
 	    bin[i] = un&0xff;
 	    un >>= 8;
 	}
@@ -154,8 +154,10 @@ ossl_bn_initialize(int argc, VALUE *argv, VALUE self)
 
 	GetBN(self, bn);
 	if (!BN_bin2bn(bin, (int)sizeof(BDIGIT)*RBIGNUM_LENINT(str), bn)) {
+	    xfree(bin);
 	    ossl_raise(eBNError, NULL);
 	}
+	xfree(bin);
 	if (!RBIGNUM_SIGN(str)) BN_set_negative(bn, 1);
 	return self;
     }