diff --git a/internal/compact_lang_det_hint_code.cc b/internal/compact_lang_det_hint_code.cc
index fc1f0ae..6c352e7 100644
--- a/internal/compact_lang_det_hint_code.cc
+++ b/internal/compact_lang_det_hint_code.cc
@@ -1448,6 +1448,8 @@ void SetCLDTLDHint(const char* tld, CLDLangPriors* langpriors) {
   if (len > 3) {return;}        // Ignore if more than three letters
   char local_tld[4];
   strncpy(local_tld, tld, len);
+  local_tld[3] = '\0';          // Safety move
+  // Lowercase
   for (int i = 0; i < len; ++i) {local_tld[i] |= 0x20;}
   const TLDLookup* entry = DoTLDLookup(local_tld,
                                        kCLDTLDHintTable,