CVE-2026-79611
VMX: VMentry failure with branch tracing and blocked states
- State
- Published
- Severity
- 5.5 Medium
- Published
- Oct 13, 2026
- Updated
- Oct 20, 2026
- Reserved
- Aug 25, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 5.5 Medium | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H | CISA-ADP |
Weaknesses
- CWE-843 Access of Resource Using Incompatible Type ('Type Confusion')
Affected Products
| Product | Versions |
|---|---|
XenXen |
|
References
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