[ CVE-2026-79611 · Published 13 Oct 2026 ]
Vulnerability in Xen
[ Description ]Official 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.
[ Fixes ]Fixes and patches
No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.
[ Advisories ]Government CERT advisories
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CERT-FRCERTFR-2026-AVI-1302
Multiple vulnerabilities in Xen Translated from French
Multiple vulnerabilities have been discovered in Xen. Some of them allow an attacker to cause arbitrary code execution, privilege escalation and a breach of data confidentiality.
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BSI CERT-BundWID-SEC-2026-3930
Xen: Multiple vulnerabilities Translated from German