CVE-2021-3308 Denial of service in n/a
A malicious HVM guest with PCI pass-through can exhaust system IDT vectors, causing a denial of service for other guests or the host.
- 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-2021-3308?
CVE-2021-3308 is a medium-severity denial of service vulnerability in Fedoraproject Fedora, published on 26 Jan 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 4.12.3 through 4.12.4 and 4.13.1 through 4.14.x. An x86 HVM guest with PCI pass through devices can force the allocation of all IDT vectors on the system by rebooting itself with MSI or MSI-X capabilities enabled and entries setup. Such reboots will leak any vectors used by the MSI(-X) entries that the guest might had enabled, and hence will lead to vector exhaustion on the system, not allowing further PCI pass through devices to work properly. HVM guests with PCI pass through devices can mount a Denial of Service (DoS) attack affecting the pass through of PCI devices to other guests or the hardware domain. In the latter case, this would affect the entire host.
Which versions are affected by CVE-2021-3308?
It affects 2 products.
Products include Fedoraproject Fedora, Xen Xen.
How do I fix CVE-2021-3308?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2021-3308 being exploited?
There is no known exploitation of CVE-2021-3308 in the wild and no public exploit code.
Other vulnerabilities in Fedoraproject Fedora
Sources
Also known as ALPINE-CVE-2021-3308, DEBIAN-CVE-2021-3308, GHSA-4gx5-7c23-79mh.