CVE-2026-23557

Description

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.

PUBLISHED Reserved 2026-01-14 | Published 2026-05-19 | Updated 2026-05-19 | Assigner XEN

Product status

Credits

This issue was discovered by Andrii Sultanov of Vates. finder

References

www.openwall.com/lists/oss-security/2026/04/28/11

xenbits.xen.org/xsa/advisory-484.html

xenbits.xenproject.org/xsa/advisory-484.html

cve.org (CVE-2026-23557)

nvd.nist.gov (CVE-2026-23557)

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