FreeBSD 5.1 and earlier, and Mac OS X before 10.3.4, allows remote attackers to cause a denial of service (resource exhaustion of memory buffers and system crash) via a large number of out-of-sequence TCP packets, which prevents the operating system from creating new connections.
The TCP MSS (maximum segment size) functionality in netinet allows remote attackers to cause a denial of service (resource exhaustion) via (1) a low MTU, which causes a large number of small packets to be produced, or (2) via a large number of packets with a small TCP payload, which cause a large number of calls to the resource-intensive sowakeup function.
The shmat system call in the System V Shared Memory interface for FreeBSD 5.2 and earlier, NetBSD 1.3 and earlier, and OpenBSD 2.6 and earlier, does not properly decrement a shared memory segment's reference count when the vm_map_find function fails, which could allow local users to gain read or write access to a portion of kernel memory and gain privileges.
The implementation of SYN cookies (syncookies) in FreeBSD 4.5 through 5.0-RELEASE-p3 uses only 32-bit internal keys when generating syncookies, which makes it easier for remote attackers to conduct brute force ISN guessing attacks and spoof legitimate traffic.
Integer overflow in the f_count counter in FreeBSD before 4.2 through 5.0 allows local users to cause a denial of service (crash) and possibly execute arbitrary code via multiple calls to (1) fpathconf and (2) lseek, which do not properly decrement f_count through a call to fdrop.
ISC BIND 8.3.x before 8.3.7, and 8.4.x before 8.4.3, allows remote attackers to poison the cache via a malicious name server that returns negative responses with a large TTL (time-to-live) value.
The arplookup function in FreeBSD 5.1 and earlier, Mac OS X before 10.2.8, and possibly other BSD-based systems, allows remote attackers on a local subnet to cause a denial of service (resource starvation and panic) via a flood of spoofed ARP requests.
The DNS map code in Sendmail 8.12.8 and earlier, when using the "enhdnsbl" feature, does not properly initialize certain data structures, which allows remote attackers to cause a denial of service (process crash) via an invalid DNS response that causes Sendmail to free incorrect data.
The prescan function in Sendmail 8.12.9 allows remote attackers to execute arbitrary code via buffer overflow attacks, as demonstrated using the parseaddr function in parseaddr.c.
Off-by-one error in the fb_realpath() function, as derived from the realpath function in BSD, may allow attackers to execute arbitrary code, as demonstrated in wu-ftpd 2.5.0 through 2.6.2 via commands that cause pathnames of length MAXPATHLEN+1 to trigger a buffer overflow, including (1) STOR, (2) RETR, (3) APPE, (4) DELE, (5) MKD, (6) RMD, (7) STOU, or (8) RNTO.