(RHSA-2018:2162) Important: qemu-kvm security update

Kernel-based Virtual Machine (KVM) is a full virtualization solution for Linux on a variety of architectures. The qemu-kvm packages provide the user-space component for running virtual machines that use KVM.

Security Fix(es):

• An industry-wide issue was found in the way many modern microprocessor designs have implemented speculative execution of Load & Store instructions (a commonly used performance optimization). It relies on the presence of a precisely-defined instruction sequence in the privileged code as well as the fact that memory read from address to which a recent memory write has occurred may see an older value and subsequently cause an update into the microprocessor’s data cache even for speculatively executed instructions that never actually commit (retire). As a result, an unprivileged attacker could use this flaw to read privileged memory by conducting targeted cache side-channel attacks. (CVE-2018-3639)

Note: This is the qemu-kvm side of the CVE-2018-3639 mitigation.

• QEMU: cirrus: OOB access when updating VGA display (CVE-2018-7858)

• QEMU: vga: OOB read access during display update (CVE-2017-13672)

• Qemu: Out-of-bounds read in vga_draw_text routine (CVE-2018-5683)

For more details about the security issue(s), including the impact, a CVSS score, and other related information, refer to the CVE page(s) listed in the References section.

Red Hat would like to thank Ken Johnson (Microsoft Security Response Center) and Jann Horn (Google Project Zero) for reporting CVE-2018-3639; Ross Lagerwall (Citrix.com) for reporting CVE-2018-7858; David Buchanan for reporting CVE-2017-13672; and Jiang Xin and Lin ZheCheng for reporting CVE-2018-5683.