CVE-2026-42493: x86 shadow paging is deprecated

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-28 · updated 2026-07-28
Weakness: CWE-400

Description

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.

References

https://xenbits.xenproject.org/xsa/advisory-495.html
http://www.openwall.com/lists/oss-security/2026/07/28/12
http://xenbits.xen.org/xsa/advisory-495.html

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