The gnutls_x509_dn_oid_name function in lib/x509/common.c in GnuTLS 3.0 before 3.1.20 and 3.2.x before 3.2.10 allows remote attackers to cause a denial of service (NULL pointer dereference) via a crafted X.509 certificate, related to a missing LDAP description for an OID when printing the DN.

The (1) asn1_read_value_type and (2) asn1_read_value functions in GNU Libtasn1 before 3.6 allows context-dependent attackers to cause a denial of service (NULL pointer dereference and crash) via a NULL value in an ivalue argument.

The asn1_get_bit_der function in GNU Libtasn1 before 3.6 does not properly report an error when a negative bit length is identified, which allows context-dependent attackers to cause out-of-bounds access via crafted ASN.1 data.

Multiple unspecified vulnerabilities in the DER decoder in GNU Libtasn1 before 3.6, as used in GnuTLS, allow remote attackers to cause a denial of service (out-of-bounds read) via crafted ASN.1 data.

Buffer overflow in the read_server_hello function in lib/gnutls_handshake.c in GnuTLS before 3.1.25, 3.2.x before 3.2.15, and 3.3.x before 3.3.4 allows remote servers to cause a denial of service (memory corruption) or possibly execute arbitrary code via a long session id in a ServerHello message.

lib/x509/verify.c in GnuTLS before 3.1.21 and 3.2.x before 3.2.11 treats version 1 X.509 certificates as intermediate CAs, which allows remote attackers to bypass intended restrictions by leveraging a X.509 V1 certificate from a trusted CA to issue new certificates.

lib/x509/verify.c in GnuTLS before 3.1.22 and 3.2.x before 3.2.12 does not properly handle unspecified errors when verifying X.509 certificates from SSL servers, which allows man-in-the-middle attackers to spoof servers via a crafted certificate.

The TLS implementation in GnuTLS before 2.12.23, 3.0.x before 3.0.28, and 3.1.x before 3.1.7 does not properly consider timing side-channel attacks on a noncompliant MAC check operation during the processing of malformed CBC padding, which allows remote attackers to conduct distinguishing attacks and plaintext-recovery attacks via statistical analysis of timing data for crafted packets, a related issue to CVE-2013-0169.

gnutls_cipher.c in libgnutls in GnuTLS before 2.12.17 and 3.x before 3.0.15 does not properly handle data encrypted with a block cipher, which allows remote attackers to cause a denial of service (heap memory corruption and application crash) via a crafted record, as demonstrated by a crafted GenericBlockCipher structure.

The asn1_get_length_der function in decoding.c in GNU Libtasn1 before 2.12, as used in GnuTLS before 3.0.16 and other products, does not properly handle certain large length values, which allows remote attackers to cause a denial of service (heap memory corruption and application crash) or possibly have unspecified other impact via a crafted ASN.1 structure.

Double free vulnerability in libgnutls in GnuTLS before 3.0.14 allows remote attackers to cause a denial of service (application crash) or possibly have unspecified other impact via a crafted certificate list.

The DTLS implementation in GnuTLS 3.0.10 and earlier executes certain error-handling code only if there is a specific relationship between a padding length and the ciphertext size, which makes it easier for remote attackers to recover partial plaintext via a timing side-channel attack, a related issue to CVE-2011-4108.

Buffer overflow in the gnutls_session_get_data function in lib/gnutls_session.c in GnuTLS 2.12.x before 2.12.14 and 3.x before 3.0.7, when used on a client that performs nonstandard session resumption, allows remote TLS servers to cause a denial of service (application crash) via a large SessionTicket.

Mutt 1.5.19, when linked against (1) OpenSSL (mutt_ssl.c) or (2) GnuTLS (mutt_ssl_gnutls.c), allows connections when only one TLS certificate in the chain is accepted instead of verifying the entire chain, which allows remote attackers to spoof trusted servers via a man-in-the-middle attack.