Kerberos 5 su (k5su) in FreeBSD 4.5 and earlier does not verify that a user is a member of the wheel group before granting superuser privileges, which could allow unauthorized users to execute commands as root.
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.
FreeBSD kernel 4.6 and earlier closes the file descriptors 0, 1, and 2 after they have already been assigned to /dev/null when the descriptors reference procfs or linprocfs, which could allow local users to reuse the file descriptors in a setuid or setgid program to modify critical data and gain privileges.
Integer overflow in the Berkeley Fast File System (FFS) in FreeBSD 4.6.1 RELEASE-p4 and earlier allows local users to access arbitrary file contents within FFS to gain privileges by creating a file that is larger than allowed by the virtual memory system.
Network File System (NFS) in FreeBSD 4.6.1 RELEASE-p7 and earlier, NetBSD 1.5.3 and earlier, and possibly other operating systems, allows remote attackers to cause a denial of service (hang) via an RPC message with a zero length payload, which causes NFS to reference a previous payload and enter an infinite loop.
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.
ktrace in BSD-based operating systems allows the owner of a process with special privileges to trace the process after its privileges have been lowered, which may allow the owner to obtain sensitive information that the process obtained while it was running with the extra privileges.
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.
Memory leak in FreeBSD 4.5 and earlier allows remote attackers to cause a denial of service (memory exhaustion) via ICMP echo packets that trigger a bug in ip_output() in which the reference count for a routing table entry is not decremented, which prevents the entry from being removed.