National Vulnerability Database

National Vulnerability Database

National Vulnerability
Database

CVE-2018-12891 Detail

Current 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.

Source:  MITRE
Description Last Modified:  07/02/2018
View Analysis Description

Impact

CVSS v3.0 Severity and Metrics:

Base Score: 6.5 MEDIUM
Vector: AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H (V3 legend)
Impact Score: 4.0
Exploitability Score: 2.0


Attack Vector (AV): Local
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): None
Scope (S): Changed
Confidentiality (C): None
Integrity (I): None
Availability (A): High

CVSS v2.0 Severity and Metrics:

Base Score: 4.9 MEDIUM
Vector: (AV:L/AC:L/Au:N/C:N/I:N/A:C) (V2 legend)
Impact Subscore: 6.9
Exploitability Subscore: 3.9


Access Vector (AV): Local
Access Complexity (AC): Insufficient_Info
Authentication (AU): None
Confidentiality (C): None
Integrity (I): None
Availability (A): Complete
Additional Information:
Allows disruption of service

References to Advisories, Solutions, and Tools

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Hyperlink Resource
http://www.openwall.com/lists/oss-security/2018/06/27/10 Mailing List Patch Third Party Advisory
http://www.securityfocus.com/bid/104570 Third Party Advisory VDB Entry
http://www.securitytracker.com/id/1041201 Third Party Advisory VDB Entry
http://xenbits.xen.org/xsa/advisory-264.html Patch Vendor Advisory
https://lists.debian.org/debian-lts-announce/2018/11/msg00013.html
https://security.gentoo.org/glsa/201810-06
https://support.citrix.com/article/CTX235748 Third Party Advisory
https://www.debian.org/security/2018/dsa-4236 Third Party Advisory

Technical Details

Vulnerability Type (View All)

  • Resource Management Errors (CWE-399)

Change History

4 change records found - show changes

Quick Info

CVE Dictionary Entry:
CVE-2018-12891
NVD Published Date:
07/02/2018
NVD Last Modified:
11/13/2018