CVE-2026-79611
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Xen Hypervisor VMEntry Failure Due to Debug State
Vulnerability report for CVE-2026-79611, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-10-13
Last updated on: 2026-10-20
Assigner: Xen Project
Description
Description
For XSA-308 logic was introduced, as VMX VMEntry checks do not like the
exact combination of state which occurs when #DB in intercepted, Single
Stepping is active, and blocked by STI/MovSS is active, despite this being
a legitimate state to be in. The resulting VMEntry failure is fatal to
the guest.
Sadly there is another special sub-case of the above, with branch tracing
enabled. In that case the prior adjustment would still cause a VMentry
failure, as before fatal to the guest.
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-843 | The product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type. |
