From Net-security.org: A recent (fall 2000) security fix to cron introduced an error in giving
up privileges before invoking the editor. A malicious user could
easily gain root access.
This has been fixed in version 3.0pl1-57.3 (or 3.0pl1-67 for unstable).
No exploits are known to exist, but we recommend that you upgrade your
cron packages immediately.