Greg MacManus, of iSIGHT Partners Labs, found a security problem
in several recent versions of nginx.  A stack-based buffer
overflow might occur in a worker process while handling a
specially crafted request, potentially resulting in arbitrary code
execution (CVE-2013-2028).

The problem affects nginx 1.3.9 - 1.4.0.

The problem is fixed in nginx 1.5.0, 1.4.1.

Patch for the problem can be found here:

http://nginx.org/download/patch.2013.chunked.txt

As a temporary workaround the following configuration
can be used in each server{} block:

   if ($http_transfer_encoding ~* chunked) {
       return 444;
   }

FIX: 

--- src/http/ngx_http_parse.c
+++ src/http/ngx_http_parse.c
@@ -2209,6 +2209,10 @@ data:
 
     }
 
+    if (ctx->size < 0 || ctx->length < 0) {
+        goto invalid;
+    }
+
     return rc;
 
 done: