What is CVE-2026-42493?

CVE-2026-42493 is a high-severity vulnerability in Xen, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-07-28.

How severe is CVE-2026-42493?

High severity. CVSS v3 base score is 7.5 out of 10.

Resource exhaustion in Xen

CVE-2026-42493

Addressing certain issues, in particular related to operations which may take excessively long and therefore would need preemption, has turned out overly costly. Since alternatives (HVM/PVH: HAP, PV: shim) are commonly available, the decision was to deprecate the functionality, while still retaining it for people to use at their own (security) risk. Memory-wise small enough guests may still be okay to run.

Vulnerability class: DoS (Denial of Service)

EPSS: 0.004 (37.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Xen — versions consult Xen advisory XSA-495

Weakness classification (CWE)

CWE-400 — Uncontrolled Resource Consumption

References

Frequently asked questions

What is CVE-2026-42493?: CVE-2026-42493 is a high-severity vulnerability in Xen, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-07-28.
How severe is CVE-2026-42493?: High severity. CVSS v3 base score is 7.5 out of 10.