The ELF parser (readelf.c) in file before 5.21 allows remote attackers to cause a denial of service (CPU consumption or crash) via a large number of (1) program or (2) section headers or (3) invalid capabilities.

Multiple vulnerabilities in the SACK functionality in (1) tcp_input.c and (2) tcp_usrreq.c OpenBSD 3.5 and 3.6 allow remote attackers to cause a denial of service (memory exhaustion or system crash).

The TCP stack (tcp_input.c) in OpenBSD 3.5 and 3.6 allows remote attackers to cause a denial of service (system panic) via crafted values in the TCP timestamp option, which causes invalid arguments to be used when calculating the retransmit timeout.

sshd.c in OpenSSH 3.6.1p2 and 3.7.1p2 and possibly other versions, when using privilege separation, does not properly signal the non-privileged process when a session has been terminated after exceeding the LoginGraceTime setting, which leaves the connection open and allows remote attackers to cause a denial of service (connection consumption).

TCP RST denial of service in FreeBSD.

One of the data structures that holds TCP segments in all versions of FreeBSD prior to 11.2-RELEASE-p1, 11.1-RELEASE-p12, and 10.4-RELEASE-p10 uses an inefficient algorithm to reassemble the data. This causes the CPU time spent on segment processing to grow linearly with the number of segments in the reassembly queue. An attacker who has the ability to send TCP traffic to a victim system can degrade the victim system's network performance and/or consume excessive CPU by exploiting the inefficiency of TCP reassembly handling, with relatively small bandwidth cost.

The bridge functionality in OpenBSD 3.4 and 3.5, when running a gateway configured as a bridging firewall with the link2 option for IPSec enabled, allows remote attackers to cause a denial of service (crash) via an ICMP echo (ping) packet.

OpenBSD 3.4 and NetBSD 1.6 and 1.6.1 allow remote attackers to cause a denial of service (crash) by sending an IPv6 packet with a small MTU to a listening port and then issuing a TCP connect to that port.

Integer overflow in the "Max-dotdot" CVS protocol command (serve_max_dotdot) for CVS 1.12.x through 1.12.8, and 1.11.x through 1.11.16, may allow remote attackers to cause a server crash, which could cause temporary data to remain undeleted and consume disk space.

isakmpd in OpenBSD 3.4 and earlier allows remote attackers to cause a denial of service (crash) via an ISAKMP packet with a delete payload containing a large number of SPIs, which triggers an out-of-bounds read error, as demonstrated by the Striker ISAKMP Protocol Test Suite.

OpenSSL 0.9.6 before 0.9.6d does not properly handle unknown message types, which allows remote attackers to cause a denial of service (infinite loop), as demonstrated using the Codenomicon TLS Test Tool.

Multiple memory leaks in isakmpd in OpenBSD 3.4 and earlier allow remote attackers to cause a denial of service (memory exhaustion) via certain ISAKMP packets, as demonstrated by the Striker ISAKMP Protocol Test Suite.

isakmpd in OpenBSD 3.4 and earlier allows remote attackers to cause a denial of service (infinite loop) via an ISAKMP packet with a zero-length payload, as demonstrated by the Striker ISAKMP Protocol Test Suite.

The SSL/TLS handshaking code in OpenSSL 0.9.7a, 0.9.7b, and 0.9.7c, when using Kerberos ciphersuites, does not properly check the length of Kerberos tickets during a handshake, which allows remote attackers to cause a denial of service (crash) via a crafted SSL/TLS handshake that causes an out-of-bounds read.

The do_change_cipher_spec function in OpenSSL 0.9.6c to 0.9.6k, and 0.9.7a to 0.9.7c, allows remote attackers to cause a denial of service (crash) via a crafted SSL/TLS handshake that triggers a null dereference.

Denial of service in "poll" in OpenBSD.

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.

engine.c in slaacd in OpenBSD 6.9 and 7.0 before 2022-02-21 has a buffer overflow triggerable by an IPv6 router advertisement with more than seven nameservers. NOTE: privilege separation and pledge can prevent exploitation.

slaacd in OpenBSD 6.9 and 7.0 before 2022-03-22 has an integer signedness error and resultant heap-based buffer overflow triggerable by a crafted IPv6 router advertisement. NOTE: privilege separation and pledge can prevent exploitation.

BIND 8.3.x through 8.3.3 allows remote attackers to cause a denial of service (termination due to assertion failure) via a request for a subdomain that does not exist, with an OPT resource record with a large UDP payload size.

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.

BIND 8.x through 8.3.3 allows remote attackers to cause a denial of service (crash) via SIG RR elements with invalid expiry times, which are removed from the internal BIND database and later cause a null dereference.

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.

The SYN cache (syncache) and SYN cookie (syncookie) mechanism in FreeBSD 4.5 and earlier allows remote attackers to cause a denial of service (crash) (1) via a SYN packet that is accepted using syncookies that causes a null pointer to be referenced for the socket's TCP options, or (2) by killing and restarting a process that listens on the same socket, which does not properly clear the old inpcb pointer on restart.

IPSEC implementations including (1) FreeS/WAN and (2) KAME do not properly calculate the length of authentication data, which allows remote attackers to cause a denial of service (kernel panic) via spoofed, short Encapsulating Security Payload (ESP) packets, which result in integer signedness errors.

Multiple TCP implementations could allow remote attackers to cause a denial of service (bandwidth and CPU exhaustion) by setting the maximum segment size (MSS) to a very small number and requesting large amounts of data, which generates more packets with less TCP-level data that amplify network traffic and consume more server CPU to process.

OpenBSD before 20070116 allows remote attackers to cause a denial of service (infinite loop and CPU consumption) via certain IPv6 ICMP (aka ICMP6) echo request packets.

NetBSD 1.5 and earlier and FreeBSD 4.3 and earlier allows a remote attacker to cause a denial of service by sending a large number of IP fragments to the machine, exhausting the mbuf pool.

SGI IRIX 6.5 through 6.5.12f and possibly earlier versions, and FreeBSD 3.0, allows remote attackers to cause a denial of service via a malformed IGMP multicast packet with a small response delay.

rwho daemon rwhod in FreeBSD 4.2 and earlier, and possibly other operating systems, allows remote attackers to cause a denial of service via malformed packets with a short length.

The IPSEC implementation in OpenBSD 2.7 does not properly handle empty AH/ESP packets, which allows remote attackers to cause a denial of service.

telnetd in FreeBSD 4.2 and earlier, and possibly other operating systems, allows remote attackers to cause a denial of service by specifying an arbitrary large file in the TERMCAP environmental variable, which consumes resources as the server processes the file.

The getnameinfo function in FreeBSD 4.1.1 and earlier, and possibly other operating systems, allows a remote attacker to cause a denial of service via a long DNS hostname.

NetBSD 1.4.2 and earlier allows remote attackers to cause a denial of service by sending a packet with an unaligned IP timestamp option.

IP fragment assembly in OpenBSD 2.4 allows a remote attacker to cause a denial of service by sending a large number of fragmented packets.

Operating systems with shared memory implementations based on BSD 4.4 code allow a user to conduct a denial of service and bypass memory limits (e.g., as specified with rlimits) using mmap or shmget to allocate memory and cause page faults.

IP fragmentation denial of service in FreeBSD allows a remote attacker to cause a crash.

FreeBSD allows local users to conduct a denial of service by creating a hard link from a device special file to a file on an NFS file system.

Jolt ICMP attack causes a denial of service in Windows 95 and Windows NT systems.

ICMP messages to broadcast addresses are allowed, allowing for a Smurf attack that can cause a denial of service.

Multiple TCP implementations with Protection Against Wrapped Sequence Numbers (PAWS) with the timestamps option enabled allow remote attackers to cause a denial of service (connection loss) via a spoofed packet with a large timer value, which causes the host to discard later packets because they appear to be too old.

OpenBSD kernel crash through TSS handling, as caused by the crashme program.

ip_input.c in BSD-derived TCP/IP implementations allows remote attackers to cause a denial of service (crash or hang) via crafted packets.

In FreeBSD 11.x before 11.1-RELEASE and 10.x before 10.4-RELEASE, the qsort algorithm has a deterministic recursion pattern. Feeding a pathological input to the algorithm can lead to excessive stack usage and potential overflow. Applications that use qsort to handle large data set may crash if the input follows the pathological pattern.

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.

Integer overflow in the calloc function in libc/stdlib/malloc.c in jemalloc in libc for FreeBSD 6.4 and NetBSD makes it easier for context-dependent attackers to perform memory-related attacks such as buffer overflows via a large size value, which triggers a memory allocation of one byte.

Server or client applications that call the SSL_check_chain() function during or after a TLS 1.3 handshake may crash due to a NULL pointer dereference as a result of incorrect handling of the "signature_algorithms_cert" TLS extension. The crash occurs if an invalid or unrecognised signature algorithm is received from the peer. This could be exploited by a malicious peer in a Denial of Service attack. OpenSSL version 1.1.1d, 1.1.1e, and 1.1.1f are affected by this issue. This issue did not affect OpenSSL versions prior to 1.1.1d. Fixed in OpenSSL 1.1.1g (Affected 1.1.1d-1.1.1f).

It was found in FreeBSD 8.0, 6.3 and 4.9, and OpenBSD 4.6 that a null pointer dereference in ftpd/popen.c may lead to remote denial of service of the ftpd service.