Quick answers
- Is CVE-2026-79607 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-79607 being exploited in the wild.
- How severe is CVE-2026-79607?
- Informational severity, published 13 October 2026.
- Which products and versions are affected?
- Xen 4.22.
- Is there a fix for CVE-2026-79607?
- No fixed version is recorded yet. Do not perform live updates of Xenstore, or switch to the oxenstored implementation which is not vulnerable. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-79607 attacked?
- It is attacked with local access, in an operating system.
- Am I affected by CVE-2026-79607?
- Check whether you run Xen at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
Do not perform live updates of Xenstore, or switch to the oxenstored implementation which is not vulnerable.
Technical details
A serialization bug in Xenstore's live update mechanism omits two bytes when writing state records for watches with specified watch depth, resulting in corrupted state that causes a crash or data corruption when deserialized in the new Xenstore instance. An unprivileged guest can trigger a Xenstore live update that exploits this flaw, achieving denial of service against the hypervisor's domain management capabilities. The vulnerability affects only Xen 4.22 running the C xenstore implementation; oxenstored is unaffected.
Affected products
- Xen Xen 4.22
Timeline
- 2026-10-13: advisory
- 2026-10-13: disclosed