CVE-2026-23557: Xenstored DoS via XS_RESET_WATCHES command
Any guest can cause xenstored to crash by issuing a XS_RESET_WATCHES command within a transaction due to an assert() triggering. In case xenstored was built with NDEBUG #defined nothing bad will happen, as assert() is doing nothing in this case. Note that the default is not to define NDEBUG for xenstored builds even in release builds of Xen.
Affected Software
Remediation
Patch Available
Patch Available
Patch Available
Event History
Frequently Asked Questions
What is the severity of CVE-2026-23557?
The severity of CVE-2026-23557 is medium with a CVSS score of 6.5.
What does CVE-2026-23557 affect?
CVE-2026-23557 affects the Xen Project xenstored, which is a part of the Xen hypervisor.
How do I fix CVE-2026-23557?
To fix CVE-2026-23557, you need to apply the available patch provided by the Xen Project.
What is the impact of CVE-2026-23557?
The impact of CVE-2026-23557 allows any guest to cause a denial of service by crashing xenstored.
Can the assert() in CVE-2026-23557 mitigate the issue?
If xenstored is built with NDEBUG defined, the assert() does nothing, resulting in no adverse effect from exploiting CVE-2026-23557.