Todd Miller : Security Vulnerabilities, CVEs, Published In 2007

Multiple race conditions in the (1) Sudo monitor mode and (2) Sysjail policies in Systrace on NetBSD and OpenBSD allow local users to defeat system call interposition, and consequently bypass access control policy and auditing.

sudo, when linked with MIT Kerberos 5 (krb5), does not properly check whether a user can currently authenticate to Kerberos, which allows local users to gain privileges, in a manner unintended by the sudo security model, via certain KRB5_ environment variable settings. NOTE: another researcher disputes this vulnerability, stating that the attacker must be "a user, who can already log into your system, and can already use sudo."