CVE-2021-27379 Privilege escalation in n/a

High 7.8 Published 18 Feb 2021 Updated 3 Aug 2024

Guest OS users can gain privileges or crash the host via incorrect IOMMU updates due to a missed flush in Xen.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2021-27379?

CVE-2021-27379 is a high-severity vulnerability in Debian Debian Linux, published on 18 Feb 2021. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

An issue was discovered in Xen through 4.11.x, allowing x86 Intel HVM guest OS users to achieve unintended read/write DMA access, and possibly cause a denial of service (host OS crash) or gain privileges. This occurs because a backport missed a flush, and thus IOMMU updates were not always correct. NOTE: this issue exists because of an incomplete fix for CVE-2020-15565.

Which versions are affected by CVE-2021-27379?

It affects 2 products.

Linux distribution packages (5)

`xen` SUSE:Linux Enterprise High Performance Computing 15-ESPOS	All versions	`4.10.4_24-3.56.1`
`xen` SUSE:Linux Enterprise High Performance Computing 15-LTSS	All versions	`4.10.4_24-3.56.1`
`xen` SUSE:Linux Enterprise Server 12 SP2-BCL	All versions	`4.7.6_14-43.76.1`
`xen` SUSE:Linux Enterprise Server for SAP Applications 15	All versions	`4.10.4_24-3.56.1`
`xen` SUSE:OpenStack Cloud 7	All versions	`4.7.6_14-43.76.1`

Products include Debian Debian Linux, Xen Xen.

How do I fix CVE-2021-27379?

Apply the vendor's patch.

Is CVE-2021-27379 being exploited?

There is no known exploitation of CVE-2021-27379 in the wild and no public exploit code.

All Debian Debian Linux vulnerabilities

Sources

Also known as DEBIAN-CVE-2021-27379, GHSA-f444-f4gw-jhg6, SUSE-SU-2021:1250-1, SUSE-SU-2021:1268-1, UBUNTU-CVE-2021-27379.