How severe is CVE-2026-23555?

CVE-2026-23555 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-23555 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-23555?

CVE-2026-23555 affects Xen. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-23555?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-23555 have an EU (EUVD) identifier?

Yes. CVE-2026-23555 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-14383.

When was CVE-2026-23555 published?

CVE-2026-23555 was published on 2026-03-23 and last updated on 2026-06-17.

CVE-2026-23555

CVE-2026-23555 is a high-severity vulnerability in Xen with a CVSS 3.x base score of 7.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-617.

Key facts

Severity: High (CVSS 3.x base score 7.1)
EPSS exploit prediction: 0% (8th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-14383
Weakness: CWE-617
Affected product: Xen
Published: 2026-03-23
Last modified: 2026-06-17

Description

Any guest issuing a Xenstore command accessing a node using the (illegal) node path "/local/domain/", will crash xenstored due to a clobbered error indicator in xenstored when verifying the node path. Note that the crash is forced via a failing assert() statement in xenstored. In case xenstored is being built with NDEBUG #defined, an unprivileged guest trying to access the node path "/local/domain/" will result in it no longer being serviced by xenstored, other guests (including dom0) will still be serviced, but xenstored will use up all cpu time it can get.

Frequently asked questions

What is CVE-2026-23555?: Any guest issuing a Xenstore command accessing a node using the (illegal) node path "/local/domain/", will crash xenstored due to a clobbered error indicator in xenstored when verifying the node path. Note that the crash is forced via a failing assert() statement in xenstored. In case xenstored is being built with NDEBUG #defined, an unprivileged guest trying to access the node path "/local/domain/" will result in it no longer being serviced by xenstored, other guests (including dom0) will still be serviced, but xenstored will use up all cpu time it can get.
How severe is CVE-2026-23555?: CVE-2026-23555 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-23555 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-23555?: CVE-2026-23555 affects Xen. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-23555?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-23555 have an EU (EUVD) identifier?: Yes. CVE-2026-23555 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-14383.
When was CVE-2026-23555 published?: CVE-2026-23555 was published on 2026-03-23 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:xen:xen:*:*:*:*:*:*:x86:*

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