CVE-2026-79611VMX: VMentry failure with branch tracing and blocked states
Updated under an hour ago ()
Does this affect you?
It affects Xen. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
Do this next
Free account, 1 product
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
- Not yet scored
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- XEN
- NVD analysis
- Awaiting Analysis
- Record last updated
- Oct 13, 2026
- First seen by InfoSec Signals
- Oct 13, 2026
Affected products
Xen Xen xen:xen (from the name) | consult Xen advisory XSA-518 status unknown | CNA record |
References
- https://xenbits.xenproject.org/xsa/advisory-518.html
- http://www.openwall.com/lists/oss-security/2026/10/13/7
- http://xenbits.xen.org/xsa/advisory-518.html
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.