diff --git a/lib/curl_ntlm_wb.c b/lib/curl_ntlm_wb.c
index baf579ef7..949c7fa17 100644
--- a/lib/curl_ntlm_wb.c
+++ b/lib/curl_ntlm_wb.c
@@ -295,6 +295,7 @@ static CURLcode ntlm_wb_response(struct connectdata *conn,
 
     if(len_out > MAX_NTLM_WB_RESPONSE) {
       failf(conn->data, "too large ntlm_wb response!");
+      free(buf);
       return CURLE_OUT_OF_MEMORY;
     }