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.
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.
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.
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.