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CVE-2023-46842

MEDIUMCVSS 6.5/10EPSS 8.53%

Last modified

CVE-2023-46842 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. Unlike 32-bit PV guests, HVM guests may switch freely between 64-bit and other modes. This in particular means that they may set registers used to pass 32-bit-mode hypercall arguments to values outside of the range 32-bit code would be able to set them to. When processing of hypercalls takes a considerable amount of time, the hypervisor may choose to invoke a hypercall continuation. EPSS estimates a 8.53% chance of exploitation in the next 30 days.

Description

Unlike 32-bit PV guests, HVM guests may switch freely between 64-bit and other modes. This in particular means that they may set registers used to pass 32-bit-mode hypercall arguments to values outside of the range 32-bit code would be able to set them to. When processing of hypercalls takes a considerable amount of time, the hypervisor may choose to invoke a hypercall continuation. Doing so involves putting (perhaps updated) hypercall arguments in respective registers. For guests not running in 64-bit mode this further involves a certain amount of translation of the values. Unfortunately internal sanity checking of these translated values assumes high halves of registers to always be clear when invoking a hypercall. When this is found not to be the case, it triggers a consistency check in the hypervisor and causes a crash.

Metrics

CVSS 3.1
6.5/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

EPSS Probability
8.53%

94.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
XenXen>= 3.2.0
FedoraprojectFedora38
FedoraprojectFedora40

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2023-46842?
Unlike 32-bit PV guests, HVM guests may switch freely between 64-bit and other modes. This in particular means that they may set registers used to pass 32-bit-mode hypercall arguments to values outside of the range 32-bit code would be able to set them to. When processing of hypercalls takes a considerable amount of time, the hypervisor may choose to invoke a hypercall continuation. Doing so involves putting (perhaps updated) hypercall arguments in respective registers. For guests not running in 64-bit mode this further involves a certain amount of translation of the values. Unfortunately internal sanity checking of these translated values assumes high halves of registers to always be clear when invoking a hypercall. When this is found not to be the case, it triggers a consistency check in the hypervisor and causes a crash.
How severe is CVE-2023-46842?
CVE-2023-46842 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 8.53% probability of exploitation in the next 30 days.
How do I fix CVE-2023-46842?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2023-46842?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST