mod_gnutls is an extension for Apache’s httpd. It uses the GnuTLS library to provide HTTPS. It supports some protocols and features that mod_ssl does not.
It was discovered that the authentication hook in mod_gnutls does not validate client’s certificates even when option “GnuTLSClientVerify” is set to “require”.
A remote attacker could present a crafted certificate and spoof clients data.
There is no known workaround at this time.
All mod_gnutls users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=www-apache/mod_gnutls-0.7.3"