CVE-2026-23557

The record

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 packages

Related vulnerabilities

• CVE-2026-23558 The adjustments made for XSA-379 as well as those subsequently becoming XSA-387 still… Also affects xen
• CVE-2025-54518 Improper isolation of shared resources within the CPU operation cache on Zen 2-based… Also affects xen
• CVE-2026-23554 The Intel EPT paging code uses an optimization to defer flushing of any cached EPT state… Also affects xen
• CVE-2026-23555 Any guest issuing a Xenstore command accessing a node using the (illegal) node path… Also affects xen
• CVE-2026-23553 In the context switch logic Xen attempts to skip an IBPB in the case of a vCPU returning… Also affects xen
• CVE-2025-58150 Shadow mode tracing code uses a set of per-CPU variables to avoid cumbersome parameter… Also affects xen
• CVE-2024-45818 The hypervisor contains code to accelerate VGA memory accesses for HVM guests, when the… Also affects xen
• CVE-2024-45819 PVH guests have their ACPI tables constructed by the toolstack. Also affects xen