Nevertheless! Party Metaphorically


Severity: moderate

Open Redirect



st is a module for serving static files.

An attacker is able to craft a request that results in an HTTP 301 (redirect) to an entirely different domain.

A request for: would result in a 301 to // which most browsers treat as a proper redirect as // is translated into the current schema being used.

Mitigating factor:

In order for this to work, st must be serving from the root of a server (/) rather than the typical sub directory (/static/) and the redirect URL will end with some form of URL encoded .. ("%2e%2e", "%2e.", ".%2e").

Code example (provided by Xin Gao):


var st = require('st') 
var http = require('http') 
$ curl -v http://localhost:1337//
*   Trying ::1...
* Connected to localhost (::1) port 1337 (#0)
> GET // HTTP/1.1
> Host: localhost:1337
> User-Agent: curl/7.54.0
> Accept: */*
< HTTP/1.1 301 Moved Permanently
< cache-control: public, max-age=600
< last-modified: Fri, 13 Oct 2017 22:56:33 GMT
< etag: "16777220-46488904-1507935393000"
< location: //
< Date: Fri, 13 Oct 2017 22:56:41 GMT
< Connection: keep-alive
< Content-Length: 30
* Connection #0 to host localhost left intact


Update to version 1.2.2 or later.


Thank you Rod Vagg for fixing this vulnerability in st and communicating it to us.

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Advisory timeline

  1. published

    Advisory published
    Oct 13th, 2017
  2. reported

    Initial report by Xin Gao
    Oct 13th, 2017