Always-Incorrect Control Flow Implementation Affecting xen-libs package, versions <4.10.4_16-3.41.1


Severity

Recommended
0.0
high
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.05% (16th percentile)

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  • Snyk IDSNYK-SLES150-XENLIBS-2701433
  • published14 Apr 2022
  • disclosed29 Sept 2020

Introduced: 29 Sep 2020

CVE-2020-25603  (opens in a new tab)
CWE-670  (opens in a new tab)

How to fix?

Upgrade SLES:15.0 xen-libs to version 4.10.4_16-3.41.1 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 4.14.x. There are missing memory barriers when accessing/allocating an event channel. Event channels control structures can be accessed lockless as long as the port is considered to be valid. Such a sequence is missing an appropriate memory barrier (e.g., smp_*mb()) to prevent both the compiler and CPU from re-ordering access. A malicious guest may be able to cause a hypervisor crash resulting in a Denial of Service (DoS). Information leak and privilege escalation cannot be excluded. Systems running all versions of Xen are affected. Whether a system is vulnerable will depend on the CPU and compiler used to build Xen. For all systems, the presence and the scope of the vulnerability depend on the precise re-ordering performed by the compiler used to build Xen. We have not been able to survey compilers; consequently we cannot say which compiler(s) might produce vulnerable code (with which code generation options). GCC documentation clearly suggests that re-ordering is possible. Arm systems will also be vulnerable if the CPU is able to re-order memory access. Please consult your CPU vendor. x86 systems are only vulnerable if a compiler performs re-ordering.

CVSS Scores

version 3.1