The Apache HTTP server is one of most popular web servers on the Internet.
A bug in the way Apache handles the Satisfy directive, which is used to require that certain conditions (client host, client authentication, etc) be met before access to a certain directory is granted, could allow the exposure of protected directories to unauthorized clients.
Directories containing protected data could be exposed to all visitors to the webserver.
There is no known workaround at this time.
All Apache users should upgrade to the latest version:
# emerge sync
# emerge -pv ">=www-servers/apache-2.0.51-r1"
# emerge ">=www-servers/apache-2.0.51-r1"