MIT Kerberos 5 (aka krb5) through 1.13.1 incorrectly expects that a krb5readmessage data field is represented as a string ending with a '\0' character, which allows remote attackers to (1) cause a denial of service (NULL pointer dereference) via a zero-byte version string or (2) cause a denial of service (out-of-bounds read) by omitting the '\0' character, related to appl/useruser/server.c and lib/krb5/krb/recvauth.c.
The krb5gssprocesscontexttoken function in lib/gssapi/krb5/processcontexttoken.c in the libgssapikrb5 library in MIT Kerberos 5 (aka krb5) through 1.11.5, 1.12.x through 1.12.2, and 1.13.x before 1.13.1 does not properly maintain security-context handles, which allows remote authenticated users to cause a denial of service (use-after-free and double free, and daemon crash) or possibly execute arbitrary code via crafted GSSAPI traffic, as demonstrated by traffic to kadmind.
The (1) kadm5createprincipal3 and (2) kadm5modifyprincipal functions in lib/kadm5/srv/svrprincipal.c in kadmind in MIT Kerberos 5 (aka krb5) 1.12.x and 1.13.x before 1.13.4 and 1.14.x before 1.14.1 allow remote authenticated users to cause a denial of service (NULL pointer dereference and daemon crash) by specifying KADM5POLICY with a NULL policy name.
The kdcpreauth modules in MIT Kerberos 5 (aka krb5) 1.12.x and 1.13.x before 1.13.2 do not properly track whether a client's request has been validated, which allows remote attackers to bypass an intended preauthentication requirement by providing (1) zero bytes of data or (2) an arbitrary realm name, related to plugins/preauth/otp/main.c and plugins/preauth/pkinit/pkinitsrv.c.
The processdbargs function in plugins/kdb/ldap/libkdbldap/ldapprincipal2.c in the LDAP KDB module in kadmind in MIT Kerberos 5 (aka krb5) through 1.13.4 and 1.14.x through 1.14.1 mishandles the DB argument, which allows remote authenticated users to cause a denial of service (NULL pointer dereference and daemon crash) via a crafted request to modify a principal.
The validateasrequest function in kdcutil.c in the Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) before 1.13.6 and 1.4.x before 1.14.3, when restrictanonymoustotgt is enabled, uses an incorrect client data structure, which allows remote authenticated users to cause a denial of service (NULL pointer dereference and daemon crash) via an S4U2Self request.