Multiple vulnerabilities has been found and corrected in gnutls: 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 and possibly have unspecified other impact via a malformed DSA key that triggers a free of an uninitialized pointer or double free . 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 . gnutls-cli in GnuTLS before 2.6.6 does not verify the activation and expiration times of X.509 certificates, which allows remote attackers to successfully present a certificate that is not yet valid or no longer valid, related to lack of time checks in the _gnutls_x509_verify_certificate function in lib/x509/verify.c in libgnutls_x509, as used by Exim, OpenLDAP, and libsoup . The updated packages have been patched to prevent this.