krb5: krb5: integer underflow in berval2tl_data() leads to heap out-of-bounds read

An integer underflow vulnerability was found in MIT krb5 in the berval2tldata function in plugins/kdb/ldap/libkdbldap/ldapprincipal2.c. The function performs an unsigned subtraction bvlen - 2 without a prior bounds check. When bvlen is 0 or 1, the subtraction wraps to a large value which is then...