Important kernel security update: CVE-2017-12188 and other; Virtuozzo ReadyKernel patch 35.2 for Virtuozzo 7.0.4, 7.0.4 HF3, and 7.0.5

The cumulative Virtuozzo ReadyKernel patch was updated with security and stability fixes. The patch applies to Virtuozzo kernels 3.10.0-514.16.1.vz7.30.10 (Virtuozzo 7.0.4), 3.10.0-514.16.1.vz7.30.15 (Virtuozzo 7.0.4 HF3), and 3.10.0-514.26.1.vz7.33.22 (Virtuozzo 7.0.5).
Vulnerability id: CVE-2017-12188
Linux kernel built with the KVM virtualisation support (CONFIG_KVM), with nested virtualisation (nVMX) feature enabled (nested=1), is vulnerable to a stack buffer overflow issue. It could occur while traversing guest pagetable entries to resolve guest virtual address. A guest system could use this flaw to crash the host kernel resulting in DoS, or potentially execute arbitrary code on the host.

Vulnerability id: CVE-2016-8399
A flaw was found in the Linux networking subsystem where a local attacker with CAP_NET_ADMIN capabilities could cause an out-of-bounds memory access by creating a smaller-than-expected ICMP header and sending to its destination via sendto().

Vulnerability id: CVE-2017-12190
It was found that in the Linux kernel through v4.14-rc5, bio_map_user_iov() and bio_unmap_user() in ‘block/bio.c’ do unbalanced pages refcounting if IO vector has small consecutive buffers belonging to the same page. bio_add_pc_page() merges them into one, but the page reference is never dropped, causing a memory leak and possible system lockup due to out-of-memory condition.