CVE-2020-15564 Information

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.

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

Reference

http://www.openwall.com/lists/oss-security/2020/07/07/5 http://xenbits.xen.org/xsa/advisory-327.html https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/MXESCOVI7AVRNC7HEAMFM7PMEO6D3AUH/ https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VB3QJJZV23Z2IDYEMIHELWYSQBUEW6JP/ https://security.gentoo.org/glsa/202007-02 https://www.debian.org/security/2020/dsa-4723

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

CHANGED

Integrity Impact

NONE

Availability Impact

NONE

Base Score

HIGH

Base Severity

6.5