CVE-2018-12891

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Summary

CVECVE-2018-12891
StatePUBLIC
Assigner[email protected]
Source PriorityCVE Program / NVD first with legacy fallback
Published2018-07-02 17:29:00 UTC
Updated2019-10-03 00:03:00 UTC
DescriptionAn 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.

Risk And Classification

Problem Types: NVD-CWE-noinfo

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Debian Debian Linux 8.0 All All All
Operating System Debian Debian Linux 9.0 All All All
Operating System Debian Debian Linux 8.0 All All All
Operating System Debian Debian Linux 9.0 All All All
Operating System Xen Xen All All All All

References

ReferenceSourceLinkTags
oss-security - Xen Security Advisory 264 (CVE-2018-12891) - preemption checks bypassed in x86 PV MM handling MLIST www.openwall.com Mailing List, Patch, Third Party Advisory
[SECURITY] [DLA 1577-1] xen security update MLIST lists.debian.org Issue Tracking, Third Party Advisory
Xen: Multiple vulnerabilities (GLSA 201810-06) — Gentoo security GENTOO security.gentoo.org Third Party Advisory
XSA-264 - Xen Security Advisories CONFIRM xenbits.xen.org Patch, Vendor Advisory
Xen PV MMU Preemption Lets Local Users on a Guest System Cause Denial of Service Conditions on the Host System - SecurityTracker SECTRACK www.securitytracker.com Third Party Advisory, VDB Entry
Xen CVE-2018-12891 Local Denial of Service Vulnerability BID www.securityfocus.com Third Party Advisory, VDB Entry
Debian -- Security Information -- DSA-4236-1 xen DEBIAN www.debian.org Third Party Advisory
Citrix XenServer Multiple Security Updates CONFIRM support.citrix.com Third Party Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Legacy QID Mappings

  • 500750 Alpine Linux Security Update for xen
  • 504527 Alpine Linux Security Update for xen
  • 710221 Gentoo Linux Xen Multiple Vulnerabilities (GLSA 201810-06)
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