nginx 0.8.43 *) Feature: large geo ranges base loading speed-up. *) Bugfix: an error_page redirection to "location /zero { return 204; }" without changing status code kept the error body; the bug had appeared in 0.8.42. *) Bugfix: nginx might close IPv6 listen socket during reconfiguration. Thanks to Maxim Dounin. *) Bugfix: the $uid_set variable may be used at any request processing stage.

--- a/src/http/ngx_http_header_filter_module.c
+++ b/src/http/ngx_http_header_filter_module.c
@@ -170,6 +170,10 @@ ngx_http_header_filter(ngx_http_request_
 #endif
     u_char                     addr[NGX_SOCKADDR_STRLEN];
 
+    if (r->header_sent) {
+        return NGX_OK;
+    }
+
     r->header_sent = 1;
 
     if (r != r->main) {