diff --git a/Modules/expat/xmltok_ns.c b/Modules/expat/xmltok_ns.c
index 919c74e..e1b46a7 100644
--- a/Modules/expat/xmltok_ns.c
+++ b/Modules/expat/xmltok_ns.c
@@ -89,7 +89,7 @@ NS(XmlInitEncoding)(INIT_ENCODING *p, const ENCODING **encPtr,
 static const ENCODING *
 NS(findEncoding)(const ENCODING *enc, const char *ptr, const char *end) {
 #  define ENCODING_MAX 128
-  char buf[ENCODING_MAX];
+  char buf[ENCODING_MAX] = {0};
   char *p = buf;
   int i;
   XmlUtf8Convert(enc, &ptr, end, &p, p + ENCODING_MAX - 1);