In Sudo before 1.8.28, an attacker with access to a Runas ALL sudoer account can bypass certain policy blacklists and session PAM modules, and can cause incorrect logging, by invoking sudo with a crafted user ID. For example, this allows bypass of !r

Todd Miller's sudo version 1.8.20p1 and earlier is vulnerable to an input validation (embedded newlines) in the get_process_ttyname() function resulting in information disclosure and command execution.