1 files changed, 3 insertions, 1 deletions
diff --git a/lib/sendf.c b/lib/sendf.c
index 99e3f65f8..fd58220d9 100644
--- a/lib/sendf.c
+++ b/lib/sendf.c
@@ -140,8 +140,10 @@ void Curl_failf(struct SessionHandle *data, const char *fmt, ...)
 {
   va_list ap;
   va_start(ap, fmt);
-  if(data->set.errorbuffer)
+  if(data->set.errorbuffer && !data->state.errorbuf) {
     vsnprintf(data->set.errorbuffer, CURL_ERROR_SIZE, fmt, ap);
+    data->state.errorbuf = TRUE; /* wrote error string */
+  }
   va_end(ap);
 }