diff --git a/3party/jansson/src/load.c b/3party/jansson/src/load.c
index 3cc7d0faa2..7232d31b78 100644
--- a/3party/jansson/src/load.c
+++ b/3party/jansson/src/load.c
@@ -525,6 +525,7 @@ static int lex_scan_number(lex_t *lex, int c, json_error_t *error)
     lex_unget_unsave(lex, c);
 
     saved_text = strbuffer_value(&lex->saved_text);
+    errno = 0;
     value = strtod(saved_text, &end);
     assert(end == saved_text + lex->saved_text.length);