CVE-2020-15564

Description

An issue was discovered in Xen through 4.13.x, allowing Arm guest OS users to cause a hypervisor crash because of a missing alignment check in VCPUOP_register_vcpu_info. The hypercall VCPUOP_register_vcpu_info is used by a guest to register a shared region with the hypervisor. The region will be mapped into Xen address space so it can be directly accessed. On Arm, the region is accessed with instructions that require a specific alignment. Unfortunately, there is no check that the address provided by the guest will be correctly aligned. As a result, a malicious guest could cause a hypervisor crash by passing a misaligned address. A malicious guest administrator may cause a hypervisor crash, resulting in a Denial of Service (DoS). All Xen versions are vulnerable. Only Arm systems are vulnerable. x86 systems are not affected.

How to fix CVE-2020-15564

To remediate CVE-2020-15564, upgrade the affected package to a fixed version below.

• —upgrade to 4.12.3-r2 or later
• —upgrade to 4.11.4+24-gddaaccbbab-1 or later

Is CVE-2020-15564 being exploited?

Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.

Affected packages (2)

• from 0, < 4.12.3-r2
• from 0, < 4.11.4+24-gddaaccbbab-1

CVSS scores

References (2)

• ADVISORYsecurity.alpinelinux.org/vuln/CVE-2020-15564
• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2020-15564