Zimbra Collaboration: CVE-2023-0286: Type Confusion vulnerability.

Description

There is a type confusion vulnerability relating to x.400 address processing inside an x.509 generalname. x.400 addresses were parsed as an asn1_string but the public structure definition for general_name incorrectly specified the type of the x400address field as asn1_type. this field is subsequently interpreted by the openssl function general_name_cmp as an asn1_type rather than an asn1_string. when crl checking is enabled (i.e. the application sets the x509_v_flag_crl_check flag), this vulnerability may allow an attacker to pass arbitrary pointers to a memcmp call, enabling them to read memory contents or enact a denial of service. in most cases, the attack requires the attacker to provide both the certificate chain and crl, neither of which need to have a valid signature. if the attacker only controls one of these inputs, the other input must already contain an x.400 address as a crl distribution point, which is uncommon. as such, this vulnerability is most likely to only affect applications which have implemented their own functionality for retrieving crls over a network.