diff --git a/src/api/variables.c b/src/api/variables.c
index 9ef57436b2..7a9ee74f56 100644
--- a/src/api/variables.c
+++ b/src/api/variables.c
@@ -175,7 +175,7 @@ int escape_json_string(char *dest, int dl, char *src, int sl) {
         unsigned char c = (unsigned char)src[i];
         if (c >= 32)
             dest[j++] = src[i];
-        else
+        else if (c > 0)
             strlcatf(dest, sl, j, "%%x%02X", c);
     }
     dest[j++] = '"';