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6.2
CVE-2020-29567: Xen 4.14 on x86 can freeze CPU with PCI passthrough
CVE-2020-29567 · published 5 years ago
Summary
The Xen hypervisor version 4.14 used in Debian and Alpine Linux can lock up a physical CPU when a virtual machine is given direct access to a PCI device. This makes the whole host unusable and can be triggered only by guests that use PCI passthrough on x86 systems. Apply the latest Xen updates from your distribution or upgrade to a newer Xen release to prevent the problem.
What to do
- Update debian xen to version 4.14.0+88-g1d1d1f5391-1.
- Update alpine xen to version 4.14.1-r0.
Affected software
| Ecosystem | Vendor | Product | Affected versions |
|---|---|---|---|
| Debian:12 | debian | xen |
< 4.14.0+88-g1d1d1f5391-1 Fix: upgrade to 4.14.0+88-g1d1d1f5391-1
|
| Debian:13 | debian | xen |
< 4.14.0+88-g1d1d1f5391-1 Fix: upgrade to 4.14.0+88-g1d1d1f5391-1
|
| Debian:14 | debian | xen |
< 4.14.0+88-g1d1d1f5391-1 Fix: upgrade to 4.14.0+88-g1d1d1f5391-1
|
| Alpine:v3.13 | alpine | xen |
< 4.14.1-r0 Fix: upgrade to 4.14.1-r0
|
| – | xen | xen |
<= 4.14.0 cpe:2.3:o:xen:xen:*:*:*:*:*:*:x86:* |
| – | fedoraproject | fedora |
33 cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* |
Original advisory text
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-allocati...
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.
References
- https://security-tracker.debian.org/tracker/CVE-2020-29567 Vendor Advisory
- https://security.alpinelinux.org/vuln/CVE-2020-29567 Vendor Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro...
- https://security.gentoo.org/glsa/202107-30 Third Party Advisory
- https://xenbits.xenproject.org/xsa/advisory-356.html Patch Vendor Advisory
Severity
6.2
Medium
Type
CWE-770Allocation of Resources Without Limits
Timeline
Published15 Dec 2020
Updated4 Nov 2026
First seen11 Sep 2026
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