CVE-2026-42488: x86: mismatched mapcache metadata

Severity: high (CVSS 8.1 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: 2026-06-18 · updated 2026-06-22
Weakness: CWE-119

Description

Some shadow paging errors paths will switch the page-tables without updating the currently running vCPU reference. This causes a mismatch between the loaded page-tables and the mapcache metadata which can lead to corruption of the mapcache.

References

https://xenbits.xenproject.org/xsa/advisory-494.html
http://www.openwall.com/lists/oss-security/2026/06/09/14
http://xenbits.xen.org/xsa/advisory-494.html

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