Jonathan Looney discovered that the Linux kernel default MSS is hard-coded to 48 bytes. This allows a remote peer to fragment TCP resend queues significantly more than if a larger MSS were enforced. A remote attacker could use this to cause a denial of service. This has been fixed in stable kernel releases 4.4.182, 4.9.182, 4.14.127, 4.19.52, 5.1.11, and is fixed in commits 967c05aee439e6e5d7d805e195b3a20ef5c433d6 and 5f3e2bf008c2221478101ee72f5cb4654b9fc363.

The TCP implementation in (1) Linux, (2) platforms based on BSD Unix, (3) Microsoft Windows, (4) Cisco products, and probably other operating systems allows remote attackers to cause a denial of service (connection queue exhaustion) via multiple vectors that manipulate information in the TCP state table, as demonstrated by sockstress.

The nl_fib_input function in fib_frontend.c in the Linux kernel before 2.6.15 does not check for valid lengths of the header and payload, which allows remote attackers to cause a denial of service (invalid memory reference) via malformed fib_lookup netlink messages.

Multiple "range checking flaws" in the ISO9660 filesystem handler in Linux 2.6.11 and earlier may allow attackers to cause a denial of service or corrupt memory via a crafted filesystem.

The load_elf_library in the Linux kernel before 2.6.11.6 allows local users to cause a denial of service (kernel crash) via a crafted ELF library or executable, which causes a free of an invalid pointer.

Buffer overflow in the MoxaDriverIoctl function for the moxa serial driver (moxa.c) in Linux 2.2.x, 2.4.x, and 2.6.x before 2.6.22 allows local users to execute arbitrary code via a certain modified length value.

Race condition in the setsid function in Linux before 2.6.8.1 allows local users to cause a denial of service (crash) and possibly access portions of kernel memory, related to TTY changes, locking, and semaphores.

Multiple drivers in Linux kernel 2.4.19 and earlier do not properly mark memory with the VM_IO flag, which causes incorrect reference counts and may lead to a denial of service (kernel panic) when accessing freed kernel pages.

Certain USB drivers in the Linux 2.4 kernel use the copy_to_user function on uninitialized structures, which could allow local users to obtain sensitive information by reading memory that was not cleared from previous usage.

ifconfig, when used on the Linux kernel 2.2 and later, does not report when the network interface is in promiscuous mode if it was put in promiscuous mode using PACKET_MR_PROMISC, which could allow attackers to sniff the network without detection, as demonstrated using libpcap.