CVE-2026-23556 oxenstored keeps quota related use counts across domain destruction
A flaw in Xen's oxenstored leaks quota usage counts, allowing a new domain to exhaust its quota prematurely and causing denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-23556?
CVE-2026-23556 is a critical denial of service vulnerability in oxenstored, published on 9 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
When oxenstored is tearing a domain down, the node data is cleaned up but the usage counts are leaked.
When the domain ID is eventually reused, the new domain can create fewer nodes before beeing deemed to be over quota.
Weakness: CWE-281
Which versions are affected by CVE-2026-23556?
How do I fix CVE-2026-23556?
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-2026-23556 being exploited?
There is no known exploitation of CVE-2026-23556 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-23556, GHSA-qcp2-2xf6-hw26, UBUNTU-CVE-2026-23556.