diff --git a/src/util/unicode.c b/src/util/unicode.c
index dd8e03814..c4dfb40e2 100644
--- a/src/util/unicode.c
+++ b/src/util/unicode.c
@@ -60,6 +60,10 @@ int unicode_utf8_mkname(utf8_t * op, size_t outlen, const utf8_t * ip)
         }
         ip += size;
     }
+    if (outlen <= 0) {
+        return ENOMEM;
+    }
+    *op = 0;
     return 0;
 }