CVE-2026-79611
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.
- Score
- CVSS 3.1 5.5 Medium
- Status
- Awaiting Analysis - security@xen.org
- Published
- 2026-10-13
- Last modified
- 2026-10-20
- Weaknesses
- CWE-843
Affected products
References
- https://xenbits.xenproject.org/xsa/advisory-518.html
- http://xenbits.xen.org/xsa/advisory-518.html
- http://www.openwall.com/lists/oss-security/2026/10/13/7
