CVE-2018-16882 Information

Description

A use-after-free issue was found in the way the Linux kernel’s KVM hypervisor processed posted interrupts when nested(=1) virtualization is enabled. In nested_get_vmcs12_pages() in case of an error while processing posted interrupt address it unmaps the ‘pi_desc_page’ without resetting ‘pi_desc’ descriptor address which is later used in pi_test_and_clear_on(). A guest user/process could use this flaw to crash the host kernel resulting in DoS or potentially gain privileged access to a system. Kernel versions before 4.14.91 and before 4.19.13 are vulnerable.

CVSS Vector

CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Reference

http://www.securityfocus.com/bid/106254 https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16882 https://lwn.net/Articles/775720/ https://lwn.net/Articles/775721/ https://marc.info/?l=kvm&m=154514994222809&w=2 https://support.f5.com/csp/article/K80557033 https://usn.ubuntu.com/3871-1/ https://usn.ubuntu.com/3871-3/ https://usn.ubuntu.com/3871-4/ https://usn.ubuntu.com/3871-5/ https://usn.ubuntu.com/3872-1/ https://usn.ubuntu.com/3878-1/ https://usn.ubuntu.com/3878-2/

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

CHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

HIGH

Base Severity

8.8