In MIT Kerberos 5 (aka krb5) before 1.21.3, an attacker can cause invalid memory reads during GSS message token handling by sending message tokens with invalid length fields.
https://web.mit.edu/kerberos/www/advisories/
https://github.com/krb5/krb5/commit/55fbf435edbe2e92dd8101669b1ce7144bc96fef