CVE - CVE-2018-12891

CVE-ID
CVE-2018-12891	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
Description
An issue was discovered in Xen through 4.10.x. Certain PV MMU operations may take a long time to process. For that reason Xen explicitly checks for the need to preempt the current vCPU at certain points. A few rarely taken code paths did bypass such checks. By suitably enforcing the conditions through its own page table contents, a malicious guest may cause such bypasses to be used for an unbounded number of iterations. A malicious or buggy PV guest may cause a Denial of Service (DoS) affecting the entire host. Specifically, it may prevent use of a physical CPU for an indeterminate period of time. All Xen versions from 3.4 onwards are vulnerable. Xen versions 3.3 and earlier are vulnerable to an even wider class of attacks, due to them lacking preemption checks altogether in the affected code paths. Only x86 systems are affected. ARM systems are not affected. Only multi-vCPU x86 PV guests can leverage the vulnerability. x86 HVM or PVH guests as well as x86 single-vCPU PV ones cannot leverage the vulnerability.
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
BID:104570 URL:http://www.securityfocus.com/bid/104570 CONFIRM:http://xenbits.xen.org/xsa/advisory-264.html CONFIRM:https://support.citrix.com/article/CTX235748 DEBIAN:DSA-4236 URL:https://www.debian.org/security/2018/dsa-4236 GENTOO:GLSA-201810-06 URL:https://security.gentoo.org/glsa/201810-06 MLIST:[debian-lts-announce] 20181112 [SECURITY] [DLA 1577-1] xen security update URL:https://lists.debian.org/debian-lts-announce/2018/11/msg00013.html MLIST:[oss-security] 20180627 Xen Security Advisory 264 (CVE-2018-12891) - preemption checks bypassed in x86 PV MM handling URL:http://www.openwall.com/lists/oss-security/2018/06/27/10 SECTRACK:1041201 URL:http://www.securitytracker.com/id/1041201
Assigning CNA
MITRE Corporation
Date Record Created
20180626	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20180626)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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