Index: SWIG/_aes.i
===================================================================
--- SWIG/_aes.i	(revision 724)
+++ SWIG/_aes.i	(working copy)
@@ -64,6 +64,7 @@
     const void *buf;
     Py_ssize_t len;
     unsigned char *out;
+    PyObject *res;
 
     if (PyObject_AsReadBuffer(in, &buf, &len) == -1)
         return NULL;
@@ -76,7 +77,9 @@
         AES_encrypt((const unsigned char *)in, out, key);
     else
         AES_decrypt((const unsigned char *)in, out, key);
-    return PyString_FromStringAndSize((char*)out, outlen);
+    res = PyString_FromStringAndSize((char*)out, outlen);
+    PyMem_Free(out);
+    return res;
 }
 
 int AES_type_check(AES_KEY *key) {