Security experts have discovered a hole in Apache web server that allows remote attackers to access internal servers. The weakness in 1.3 and all 2.x versions of the Apache HTTP Server can be exploited only under certain conditions. Apache issued a patch for those who compile their own installations of the webserver. It wouldn’t be surprising to see Linux distributions release their own security updates in the next few days. Adding a simple forward slash to certain configurations, for example, will go a long way to protecting sensitive systems.
Source: https://thehackernews.com/2011/10/apache-patch-released-for-reverse-proxy.html