Race Condition Affecting xen-libs package, versions <4.10.4_10-3.31.1


Severity

Recommended
0.0
high
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.05% (16th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications

Snyk Learn

Learn about Race Condition vulnerabilities in an interactive lesson.

Start learning
  • Snyk IDSNYK-SLES150-XENLIBS-2708604
  • published14 Apr 2022
  • disclosed17 Jun 2020

Introduced: 17 Jun 2020

CVE-2020-11739  (opens in a new tab)
CWE-362  (opens in a new tab)

How to fix?

Upgrade SLES:15.0 xen-libs to version 4.10.4_10-3.31.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream xen-libs package and not the xen-libs package as distributed by SLES. See How to fix? for SLES:15.0 relevant fixed versions and status.

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.

CVSS Scores

version 3.1