7.2 - RHSA-2016:1943

Problem Description:

An update for kvm is now available for Red Hat Enterprise Linux 5.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Desktop Multi OS (v. 5 client) - x86_64 Red Hat Enterprise Linux Virtualization (v. 5 server) - x86_64

3. Description:

KVM (for Kernel-based Virtual Machine) is a full virtualization solution for Linux on x86 hardware. Using KVM, one can run multiple virtual machines running unmodified Linux or Windows images. Each virtual machine has private virtualized hardware: a network card, disk, graphics adapter, etc.

Security Fix(es):

* An out-of-bounds read/write access flaw was found in the way QEMU's VGA emulation with VESA BIOS Extensions (VBE) support performed read/write operations using I/O port methods. A privileged guest user could use this flaw to execute arbitrary code on the host with the privileges of the host's QEMU process. (CVE-2016-3710)

* Quick Emulator(QEMU) built with the virtio framework is vulnerable to an unbounded memory allocation issue. It was found that a malicious guest user could submit more requests than the virtqueue size permits. Processing a request allocates a VirtQueueElement results in unbounded memory allocation on the host controlled by the guest. (CVE-2016-5403)

Red Hat would like to thank Wei Xiao (360 Marvel Team) and Qinghao Tang (360 Marvel Team) for reporting CVE-2016-3710 and hongzhenhao (Marvel Team) for reporting CVE-2016-5403.

4. Solution:

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

Note: The procedure in the Solution section must be performed before this update will take effect.

5. Bugs fixed (https://bugzilla.redhat.com/):

1331401 - CVE-2016-3710 qemu: incorrect banked access bounds checking in vga module 1358359 - CVE-2016-5403 Qemu: virtio: unbounded memory allocation on host via guest leading to DoS