CVE-2019-19577

Publication date 11 December 2019

Last updated 24 July 2024


Ubuntu priority

Cvss 3 Severity Score

7.2 · High

Score breakdown

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.

Read the notes from the security team

Status

Package Ubuntu Release Status
xen 24.10 oracular
Not affected
24.04 LTS noble
Not affected
23.10 mantic
Not affected
23.04 lunar
Not affected
22.10 kinetic
Not affected
22.04 LTS jammy
Not affected
21.10 impish
Not affected
21.04 hirsute
Not affected
20.10 groovy
Not affected
20.04 LTS focal
Not affected
19.10 eoan Ignored end of life
19.04 disco Ignored end of life
18.04 LTS bionic
Needs evaluation
16.04 LTS xenial
Needs evaluation
14.04 LTS trusty Not in release

Notes


mdeslaur

hypervisor packages are in universe. For issues in the hypervisor, add appropriate tags to each section, ex: Tags_xen: universe-binary

Severity score breakdown

Parameter Value
Base score 7.2 · High
Attack vector Physical
Attack complexity Low
Privileges required High
User interaction None
Scope Changed
Confidentiality High
Integrity impact High
Availability impact High
Vector CVSS:3.1/AV:P/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H