CVE-2026-62426 sysctl and platform-op locks open to abuse
An attacker can cause a denial of service in the Xen hypervisor by abusing unfair system-wide locks in sysctl operations.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-62426?
CVE-2026-62426 is a high-severity denial of service vulnerability in Xen, published on 28 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
[This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.]
To manage the system, sysctl and platform operations are used by the control domain or a possible Xenstore domain. Some of these operations may not be executed in parallel, so a system-wide lock each is used. The way those locks are acquired is, however, not providing any fairness. Furthermore, with XSM/Flask in use, the lock acquire will, for some operations, occur ahead of any permission checking.
The sysctl issue is CVE-2026-62426.
The platform-op issue is CVE-2026-62427.
Which versions are affected by CVE-2026-62426?
How do I fix CVE-2026-62426?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-62426 being exploited?
There is no known exploitation of CVE-2026-62426 in the wild and no public exploit code.
Sources
Also known as ALPINE-CVE-2026-62426, DEBIAN-CVE-2026-62426, GHSA-f8j9-mrwg-r7g5, UBUNTU-CVE-2026-62426.