CVE-2015-0282 Signature forgery This issue only affects versions of GnuTLS prior to 3.1.0 (released in 2012). These versions don't verify the RSA PKCS #1 signature algorithm to match the signature algorithm in the certificate, leading to a potential downgrade to a disallowed algorithm, such as MD5, without detecting it.
Recommendation: Upgrade to GnuTLS 3.1.0, or later. A patch will be included in gnutls_2_12_x branch for the users of that version that cannot upgrade.