GnuTLS is an open-source implementation of TLS 1.0 and SSL 3.0.
Martin von Gagern reported that the _gnutls_x509_verify_certificate() function in lib/x509/verify.c trusts certificate chains in which the last certificate is an arbitrary trusted, self-signed certificate.
A remote attacker could exploit this vulnerability and spoof arbitrary names to conduct Man-In-The-Middle attacks and intercept sensitive information.
There is no known workaround at this time.
All GnuTLS users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=net-libs/gnutls-2.4.1-r2"