CVE ID:	CVE-2018-16882
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.
Test IDs:	None available
Cross References:	Common Vulnerability Exposure (CVE) ID: CVE-2018-16882 106254 http://www.securityfocus.com/bid/106254 USN-3871-1 https://usn.ubuntu.com/3871-1/ USN-3871-3 https://usn.ubuntu.com/3871-3/ USN-3871-4 https://usn.ubuntu.com/3871-4/ USN-3871-5 https://usn.ubuntu.com/3871-5/ USN-3872-1 https://usn.ubuntu.com/3872-1/ USN-3878-1 https://usn.ubuntu.com/3878-1/ USN-3878-2 https://usn.ubuntu.com/3878-2/ https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16882 https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16882 https://lwn.net/Articles/775720/ https://lwn.net/Articles/775720/ https://lwn.net/Articles/775721/ https://lwn.net/Articles/775721/ https://marc.info/?l=kvm&m=154514994222809&w=2 https://marc.info/?l=kvm&m=154514994222809&w=2 https://support.f5.com/csp/article/K80557033 https://support.f5.com/csp/article/K80557033