CVE-2026-79611
MEDIUMDescription
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.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Exploit Intelligence
Low risk: more likely to be exploited than 5% of all known CVEs.
References
Related Vulnerabilities
Other CWE-843 (Type Confusion) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2011-0611 | High | 8.8 | 99% | KEV | Fix |
| CVE-2012-0507 | Critical | 9.8 | 98% | KEV + Ransom | - |
| CVE-2017-8291 | High | 7.8 | 97% | KEV | Fix |
| CVE-2021-21224 | High | 8.8 | 84% | KEV | Fix |
| CVE-2019-0752 | High | 7.5 | 82% | KEV + Ransom | - |
| CVE-2017-0037 | High | 8.1 | 80% | KEV | - |
Common questions
How do I fix CVE-2026-79611?
Upgrade xen on debian 13 to 4.20.4+39-gf1e1321c87-0+deb13u1 or later.
Is CVE-2026-79611 being actively exploited?
Not that we know of. CVE-2026-79611 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.16% is the estimated probability that it will be exploited in the next 30 days. That is higher than 5% of all scored CVEs.
How severe is CVE-2026-79611?
CVE-2026-79611 has a CVSS v3 base score of 5.5, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-79611 affect?
Published advisories record a fix for xen (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2026-79611
Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-10-20.