National Vulnerability Database

National Vulnerability Database

National Vulnerability
Database

CVE-2020-11739 Detail

Current Description

An issue was discovered in Xen through 4.13.x, allowing guest OS users to cause a denial of service or possibly gain privileges because of missing memory barriers in read-write unlock paths. The read-write unlock paths don't contain a memory barrier. On Arm, this means a processor is allowed to re-order the memory access with the preceding ones. In other words, the unlock may be seen by another processor before all the memory accesses within the "critical" section. As a consequence, it may be possible to have a writer executing a critical section at the same time as readers or another writer. In other words, many of the assumptions (e.g., a variable cannot be modified after a check) in the critical sections are not safe anymore. The read-write locks are used in hypercalls (such as grant-table ones), so a malicious guest could exploit the race. For instance, there is a small window where Xen can leak memory if XENMAPSPACE_grant_table is used concurrently. A malicious guest may be able to leak memory, or cause a hypervisor crash resulting in a Denial of Service (DoS). Information leak and privilege escalation cannot be excluded.

Source:  MITRE
View Analysis Description

Severity



CVSS 3.x Severity and Metrics:

NIST CVSS score
NIST: NVD
Base Score: 7.8 HIGH
Vector:  CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

References to Advisories, Solutions, and Tools

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Hyperlink Resource
http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00006.html
http://www.openwall.com/lists/oss-security/2020/04/14/2 Mailing List Patch Third Party Advisory
http://xenbits.xen.org/xsa/advisory-314.html Patch Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/5M2XRNCHOGGTJQBZQJ7DCV6ZNAKN3LE2/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NVTP4OYHCTRU3ONFJOFJQVNDFB25KLLG/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/YMAW7D2MP6RE4BFI5BZWOBBWGY3VSOFN/ Third Party Advisory
https://security.gentoo.org/glsa/202005-08
https://xenbits.xen.org/xsa/advisory-314.html Patch Vendor Advisory

Weakness Enumeration

CWE-ID CWE Name Source
CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer NIST  

Known Affected Software Configurations Switch to CPE 2.2

Configuration 1 ( hide )
 cpe:2.3:o:xen:xen:*:*:*:*:*:*:*:*
     Show Matching CPE(s)
Up to (including)
4.13.0
 cpe:2.3:o:xen:xen:4.13.0:rc1:*:*:*:*:*:*
     Show Matching CPE(s)
 cpe:2.3:o:xen:xen:4.13.0:rc2:*:*:*:*:*:*
     Show Matching CPE(s)

Configuration 2 ( hide )
 cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
     Show Matching CPE(s)


Change History

8 change records found - show changes

Quick Info

CVE Dictionary Entry:
CVE-2020-11739
NVD Published Date:
04/14/2020
NVD Last Modified:
05/14/2020