This update for apache2 fixes the following issues: * It used to be possible to set an arbitrary $HTTP_PROXY environment variable for request handlers -- like CGI scripts -- by including a specially crafted HTTP header in the request . As a result, these server components would potentially direct all their outgoing HTTP traffic through a malicious proxy server. This patch fixes the issue: the updated Apache server ignores such HTTP headers and never sets $HTTP_PROXY for sub-processes