The gnutlsx509oid2macalgorithm function in lib/gnutlsalgorithms.c in GnuTLS before 1.4.2 allows remote attackers to cause a denial of service (crash) via a crafted X.509 certificate that uses a hash algorithm that is not supported by GnuTLS, which triggers a NULL pointer dereference.

The "record packet parsing" in GnuTLS 1.2 before 1.2.3 and 1.0 before 1.0.25 allows remote attackers to cause a denial of service, possibly related to padding bytes in gnutilscipher.c.

verify.c in GnuTLS before 1.4.4, when using an RSA key with exponent 3, does not properly handle excess data in the digestAlgorithm.parameters field when generating a hash, which allows remote attackers to forge a PKCS #1 v1.5 signature that is signed by that RSA key and prevents GnuTLS from correctly verifying X.509 and other certificates that use PKCS, a variant of CVE-2006-4339.

libtasn1 version 2.12 was released fixing the following issue:

- Corrected DER decoding issue (reported by Matthew Hall). Added self check to detect the problem, see tests/Testoverflow.c. This problem can lead to at least remotely triggered crashes, see further analysis on the libtasn1 mailing list.

http://thread.gmane.org/gmane.comp.gnu.libtasn1.general/53

Upstream and few limited details are available at:

http://thread.gmane.org/gmane.comp.gnu.libtasn1.general/54

The behavior of asn1getlengthder was changed to protect against accidental incorrect use, if though it was previously "working properly and as documented".