CVE-2023-46842: x86 HVM hypercalls may trigger Xen bug check
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.
Affected Software
Remediation
Patch Available
Patch Available
Event History
Frequently Asked Questions
What is the severity of CVE-2023-46842?
CVE-2023-46842 has been classified as a high severity vulnerability.
How do I fix CVE-2023-46842?
To address CVE-2023-46842, update the Xen Hypervisor to a version that implements the necessary security patches.
What systems are impacted by CVE-2023-46842?
CVE-2023-46842 primarily affects HVM guests running on the Xen Hypervisor.
What type of vulnerability is CVE-2023-46842?
CVE-2023-46842 is a hypervisor vulnerability related to improper handling of hypercall arguments.
Is CVE-2023-46842 exploitable remotely?
Yes, CVE-2023-46842 could potentially be exploited remotely by an attacker with access to a vulnerable HVM guest.