lib/pk-libgcrypt.c in libgnutls in GnuTLS before 2.6.6 does not properly handle invalid DSA signatures, which allows remote attackers to cause a denial of service (application crash) and possibly have unspecified other impact via a malformed DSA key that triggers a (1) free of an uninitialized pointer or (2) double free.
article.gmane.org/gmane.comp.encryption.gpg.gnutls.devel/3515
permalink.gmane.org/gmane.comp.encryption.gpg.gnutls.devel/3502
secunia.com/advisories/34842
secunia.com/advisories/35211
security.gentoo.org/glsa/glsa-200905-04.xml
thread.gmane.org/gmane.comp.encryption.gpg.gnutls.devel/3488
www.mandriva.com/security/advisories?name=MDVSA-2009:116
www.securityfocus.com/bid/34783
www.securitytracker.com/id?1022157
www.vupen.com/english/advisories/2009/1218
exchange.xforce.ibmcloud.com/vulnerabilities/50257
exchange.xforce.ibmcloud.com/vulnerabilities/50260
exchange.xforce.ibmcloud.com/vulnerabilities/50445