CVE-2019-19577

CVE Details

Release Date:

2019-12-11

Description

An issue was discovered in Xen through 4.12.x allowing x86 AMD HVM guest OS users to cause a denial of service or possibly gain privileges by triggering data-structure access during pagetable-height updates. When running on AMD systems with an IOMMU, Xen attempted to dynamically adapt the number of levels of pagetables (the pagetable height) in the IOMMU according to the guest's address space size. The code to select and update the height had several bugs. Notably, the update was done without taking a lock which is necessary for safe operation. A malicious guest administrator can cause Xen to access data structures while they are being modified, causing Xen to crash. Privilege escalation is thought to be very difficult but cannot be ruled out. Additionally, there is a potential memory leak of 4kb per guest boot, under memory pressure. Only Xen on AMD CPUs is vulnerable. Xen running on Intel CPUs is not vulnerable. ARM systems are not vulnerable. Only systems where guests are given direct access to physical devices are vulnerable. Systems which do not use PCI pass-through are not vulnerable. Only HVM guests can exploit the vulnerability. PV and PVH guests cannot. All versions of Xen with IOMMU support are vulnerable.

See more information about CVE-2019-19577 from MITRE CVE dictionary and NIST NVD

CVSS v3.0 metrics

NOTE: The following CVSS v3.0 metrics and score provided are preliminary and subject to review.

Base Score:	7.2	Base Metrics:	AV:P/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Access Vector:	Physical	Attack Complexity:	Low
Privileges Required:	High	User Interaction:	None
Scope:	Changed	Confidentiality Impact:	High
Integrity Impact:	High	Availability Impact:	High

Errata information

Platform	Errata	Release Date
Oracle VM version 3.4 (xen)	OVMSA-2020-0007	2020-03-09

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