A flaw was found in the Linux kernel present since v4.0-rc1 and through v4.13-rc4. A crafted network packet sent remotely by an attacker may force the kernel to enter an infinite loop in the cipso_v4_optptr() function in net/ipv4/cipso_ipv4.c leading to a denial-of-service. A certain non-default configuration of LSM (Linux Security Module) and NetLabel should be set up on a system before an attacker could leverage this flaw.

It was discovered in the Linux kernel before 4.11-rc8 that root can gain direct access to an internal keyring, such as '.dns_resolver' in RHEL-7 or '.builtin_trusted_keys' upstream, by joining it as its session keyring. This allows root to bypass module signature verification by adding a new public key of its own devising to the keyring.

The cookie feature in the packet action API implementation in net/sched/act_api.c in the Linux kernel 4.11.x through 4.11-rc7 mishandles the tb nlattr array, which allows local users to cause a denial of service (uninitialized memory access and refcount underflow, and system hang or crash) or possibly have unspecified other impact via "tc filter add" commands in certain contexts. NOTE: this does not affect stable kernels, such as 4.10.x, from kernel.org.

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.