lib/gnutls_pk.c in libgnutls in GnuTLS 2.5.0 through 2.6.5 generates RSA keys stored in DSA structures, instead of the intended DSA keys, which might allow remote attackers to spoof signatures on certificates or have unspecified other impact by leveraging an invalid DSA key.
http://www.vupen.com/english/advisories/2009/1218
http://www.securitytracker.com/id?1022158
http://www.securityfocus.com/bid/34783
http://www.mandriva.com/security/advisories?name=MDVSA-2009:116
http://security.gentoo.org/glsa/glsa-200905-04.xml
http://secunia.com/advisories/35211
http://secunia.com/advisories/34842
http://lists.gnu.org/archive/html/help-gnutls/2009-04/msg00018.html