CVE-2020-29567
First published: Tue Dec 15 2020(Updated: )
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.
Credit: cve@mitre.org
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Xen xen-unstable | <=4.14.0 | |
| Fedora | =33 |
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Reference Links
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/OBLV6L6Q24PPQ2CRFXDX4Q76KU776GKI/
- https://security.gentoo.org/glsa/202107-30
- https://xenbits.xenproject.org/xsa/advisory-356.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OBLV6L6Q24PPQ2CRFXDX4Q76KU776GKI/
Frequently Asked Questions
What is the severity of CVE-2020-29567?
The severity of CVE-2020-29567 is classified as high due to its potential impact on system stability.
How do I fix CVE-2020-29567?
To fix CVE-2020-29567, users should upgrade to a version of Xen that is newer than 4.14.0 or apply the relevant patches provided by their distribution.
What software is affected by CVE-2020-29567?
CVE-2020-29567 affects Xen versions up to 4.14.0 and Fedora version 33.
What are the potential impacts of CVE-2020-29567?
The potential impacts of CVE-2020-29567 include system crashes and denial of service due to incorrect handling of IRQ assignments.
Is there a workaround for CVE-2020-29567?
There are no known workarounds for CVE-2020-29567; upgrading to a patched version is recommended.
- agent/type
- collector/mitre-cve
- source/MITRE
- agent/last-modified-date
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- agent/weakness
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- vendor/xen
- canonical/xen xen-unstable
- version/xen xen-unstable/4.14.0
- vendor/fedoraproject
- canonical/fedora
- version/fedora/33