plugins/preauth/pkinit/pkinit_crypto_openssl.c in MIT Kerberos 5 (aka krb5) through 1.15.2 mishandles Distinguished Name (DN) fields, which allows remote attackers to execute arbitrary code or cause a denial of service (buffer overflow and application crash) in situations involving untrusted X.509 data, related to the get_matching_data and X509_NAME_oneline_ex functions. NOTE: this has security relevance only in use cases outside of the MIT Kerberos distribution, e.g., the use of get_matching_data in KDC certauth plugin code that is specific to Red Hat.
https://github.com/krb5/krb5/pull/707
https://github.com/krb5/krb5/commit/fbb687db1088ddd894d975996e5f6a4252b9a2b4
https://bugzilla.redhat.com/show_bug.cgi?id=1504045