Multiple vulnerabilities have been discovered in GnuTLS, a library implementing the TLS and SSL protocols. The Common Vulnerabilities and Exposures project identifies the following problems:
GnuTLS does not verify the RSA PKCS #1 signature algorithm to match the signature algorithm in the certificate, leading to a potential downgrade to a disallowed algorithm without detecting it.
It was reported that GnuTLS does not check whether the two signature algorithms match on certificate import.
For the stable distribution (wheezy), these problems have been fixed in version 2.12.20-8+deb7u3.
We recommend that you upgrade your gnutls26 packages.