You are viewing this page in an unauthorized frame window.
This is a potential security issue, you are being redirected to
https://nvd.nist.gov
An official website of the United States government
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock () or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.
An issue was discovered in Xen through 4.12.x allowing x86 PV guest OS users to gain host OS privileges by leveraging race conditions in pagetable promotion and demotion operations. There are issues with restartable PV type change operations. To avoid using shadow pagetables for PV guests, Xen exposes the actual hardware pagetables to the guest. In order to prevent the guest from modifying these page tables directly, Xen keeps track of how pages are used using a type system; pages must be "promoted" before being used as a pagetable, and "demoted" before being used for any other type. Xen also allows for "recursive" promotions: i.e., an operating system promoting a page to an L4 pagetable may end up causing pages to be promoted to L3s, which may in turn cause pages to be promoted to L2s, and so on. These operations may take an arbitrarily large amount of time, and so must be re-startable. Unfortunately, making recursive pagetable promotion and demotion operations restartable is incredibly complicated, and the code contains several races which, if triggered, can cause Xen to drop or retain extra type counts, potentially allowing guests to get write access to in-use pagetables. A malicious PV guest administrator may be able to escalate their privilege to that of the host. All x86 systems with untrusted PV guests are vulnerable. HVM and PVH guests cannot exercise this vulnerability.
NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.
Note: NVD Analysts have published a CVSS score for this CVE based on publicly available information at the time of analysis. The CNA has not provided a score within the CVE List.
NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.
Note: NVD Analysts have published a CVSS score for this CVE based on publicly available information at the time of analysis. The CNA has not provided a score within the CVE List.
References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving NIST webspace.
We have provided these links to other web sites because they
may have information that would be of interest to you. No
inferences should be drawn on account of other sites being
referenced, or not, from this page. There may be other web
sites that are more appropriate for your purpose. NIST does
not necessarily endorse the views expressed, or concur with
the facts presented on these sites. Further, NIST does not
endorse any commercial products that may be mentioned on
these sites. Please address comments about this page to nvd@nist.gov.
OR
*cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
*cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
*cpe:2.3:o:fedoraproject:fedora:29:*:*:*:*:*:*:*
*cpe:2.3:o:fedoraproject:fedora:30:*:*:*:*:*:*:*
*cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*
Added
CPE Configuration
OR
*cpe:2.3:o:opensuse:leap:15.0:*:*:*:*:*:*:*
Changed
Reference Type
http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00037.html No Types Assigned
http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00037.html Mailing List, Third Party Advisory
Changed
Reference Type
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2BQKX7M2RHCWDBKNPX4KEBI3MJIH6AYZ/ No Types Assigned
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2BQKX7M2RHCWDBKNPX4KEBI3MJIH6AYZ/ Mailing List, Third Party Advisory
Changed
Reference Type
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/I5WWPW4BSZDDW7VHU427XTVXV7ROOFFW/ No Types Assigned
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/I5WWPW4BSZDDW7VHU427XTVXV7ROOFFW/ Mailing List, Third Party Advisory
Changed
Reference Type
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IZYATWNUGHRBG6I3TC24YHP5Y3J7I6KH/ No Types Assigned
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IZYATWNUGHRBG6I3TC24YHP5Y3J7I6KH/ Mailing List, Third Party Advisory
Changed
Reference Type
https://seclists.org/bugtraq/2020/Jan/21 No Types Assigned
https://seclists.org/bugtraq/2020/Jan/21 Mailing List, Third Party Advisory
Changed
Reference Type
https://security.gentoo.org/glsa/202003-56 No Types Assigned
https://security.gentoo.org/glsa/202003-56 Third Party Advisory
Changed
Reference Type
https://www.debian.org/security/2020/dsa-4602 No Types Assigned
https://www.debian.org/security/2020/dsa-4602 Third Party Advisory