CVE-2020-29567 Denial of service in n/a
A guest with a passed-through PCI device can cause a host CPU lockup via self-interrupts, leading to a Denial of Service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2020-29567?
CVE-2020-29567 is a medium-severity denial of service vulnerability in Fedoraproject Fedora, published on 15 Dec 2020. 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 4.14.x. When moving IRQs between CPUs to distribute the load of IRQ handling, IRQ vectors are dynamically allocated and de-allocated on the relevant CPUs. De-allocation has to happen when certain constraints are met. If these conditions are not met when first checked, the checking CPU may send an interrupt to itself, in the expectation that this IRQ will be delivered only after the condition preventing the cleanup has cleared. For two specific IRQ vectors, this expectation was violated, resulting in a continuous stream of self-interrupts, which renders the CPU effectively unusable. A domain with a passed through PCI device can cause lockup of a physical CPU, resulting in a Denial of Service (DoS) to the entire host. Only x86 systems are vulnerable. Arm systems are not vulnerable. Only guests with physical PCI devices passed through to them can exploit the vulnerability.
Weakness: CWE-770
Which versions are affected by CVE-2020-29567?
It affects 2 products.
Products include Fedoraproject Fedora, Xen Xen.
How do I fix CVE-2020-29567?
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-2020-29567 being exploited?
There is no known exploitation of CVE-2020-29567 in the wild and no public exploit code.
Other vulnerabilities in Fedoraproject Fedora
Sources
Also known as ALPINE-CVE-2020-29567, DEBIAN-CVE-2020-29567, GHSA-x993-24wq-x7c4.