CVE-2021-28692 Privilege escalation in xen
Improper IOMMU timeout handling in Xen allows guest VMs to crash other guests or bypass security checks, leading to privilege escalation or denial of service.
- 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-2021-28692?
CVE-2021-28692 is a high-severity vulnerability in Xen Xen, published on 30 Jun 2021. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
inappropriate x86 IOMMU timeout detection / handling IOMMUs process commands issued to them in parallel with the operation of the CPU(s) issuing such commands. In the current implementation in Xen, asynchronous notification of the completion of such commands is not used. Instead, the issuing CPU spin-waits for the completion of the most recently issued command(s). Some of these waiting loops try to apply a timeout to fail overly-slow commands. The course of action upon a perceived timeout actually being detected is inappropriate: - on Intel hardware guests which did not originally cause the timeout may be marked as crashed, - on AMD hardware higher layer callers would not be notified of the issue, making them continue as if the IOMMU operation succeeded.
Weakness: CWE-269
Which versions are affected by CVE-2021-28692?
It affects 1 product.
Products include Xen Xen.
How do I fix CVE-2021-28692?
Apply the vendor's patch.
Is CVE-2021-28692 being exploited?
There is no known exploitation of CVE-2021-28692 in the wild and no public exploit code.
Other vulnerabilities in Xen Xen
Sources
Also known as ALPINE-CVE-2021-28692, DEBIAN-CVE-2021-28692, GHSA-23j5-p74r-rvqm, UBUNTU-CVE-2021-28692.