The kqueue mechanism in FreeBSD 4.3 through 4.6 STABLE allows local users to cause a denial of service (kernel panic) via a pipe call in which one end is terminated and an EVFILT_WRITE filter is registered for the other end.

The accept_filter mechanism in FreeBSD 4 through 4.5 does not properly remove entries from the incomplete listen queue when adding a syncache, which allows remote attackers to cause a denial of service (network service availability) via a large number of connection attempts, which fills the queue.

KAME-derived implementations of IPsec on NetBSD 1.5.2, FreeBSD 4.5, and other operating systems, does not properly consult the Security Policy Database (SPD), which could cause a Security Gateway (SG) that does not use Encapsulating Security Payload (ESP) to forward forged IPv4 packets.

FreeBSD 4.5 and earlier, and possibly other BSD-based operating systems, allows local users to write to or read from restricted files by closing the file descriptors 0 (standard input), 1 (standard output), or 2 (standard error), which may then be reused by a called setuid process that intended to perform I/O on normal files.

libutil in OpenSSH on FreeBSD 4.4 and earlier does not drop privileges before verifying the capabilities for reading the copyright and welcome files, which allows local users to bypass the capabilities checks and read arbitrary files by specifying alternate copyright or welcome files.