GnuTLS before 3.1.0 does not verify that the RSA PKCS #1 signature algorithm matches the signature algorithm in the certificate, which allows remote attackers to conduct downgrade attacks via unspecified vectors.
Exploitability
AV:NAC:LAu:NImpact
C:NI:PA:N5/AV:N/AC:L/Au:N/C:N/I:P/A:N