FreeBSD 6.3, 6.4, 7.1, and 7.2 does not enforce permissions on the SIOCSIFINFOIN6 IOCTL, which allows local users to modify or disable IPv6 network interfaces, as demonstrated by modifying the MTU.
The ptsname function in FreeBSD 6.0 through 7.0-PRERELEASE does not properly verify that a certain portion of a device name is associated with a pty of a user who is calling the ptchown function, which might allow local users to read data from the pty from another user.