A flaw was found in the Linux kernel's ext4 filesystem. A local user can cause an out-of-bound access in ext4_get_group_info function, a denial of service, and a system crash by mounting and operating on a crafted ext4 filesystem image.
A use-after-free vulnerability was found in network namespaces code affecting the Linux kernel before 4.14.11. The function get_net_ns_by_id() in net/core/net_namespace.c does not check for the net::count value after it has found a peer network in netns_ids idr, which could lead to double free and memory corruption. This vulnerability could allow an unprivileged local user to induce kernel memory corruption on the system, leading to a crash. Due to the nature of the flaw, privilege escalation cannot be fully ruled out, although it is thought to be unlikely.
The tcpmss_mangle_packet function in net/netfilter/xt_TCPMSS.c in the Linux kernel before 4.11, and 4.9.x before 4.9.36, allows remote attackers to cause a denial of service (use-after-free and memory corruption) or possibly have unspecified other impact by leveraging the presence of xt_TCPMSS in an iptables action.
The icmp_check_sysrq function in net/ipv4/icmp.c in the kernel.org projects/rt patches for the Linux kernel, as used in the kernel-rt package before 3.10.0-327.22.1 in Red Hat Enterprise Linux for Real Time 7 and other products, allows remote attackers to execute SysRq commands via crafted ICMP Echo Request packets, as demonstrated by a brute-force attack to discover a cookie, or an attack that occurs after reading the local icmp_echo_sysrq file.