CVE-2026-79609

High

Description

XPTI (Xen Page Table Isolation) was introduced to mitigate Meltdown (CVE-2017-5754, one aspect of XSA-254). This involves copying 64-bit PV guest page table entries from guest-chosen root page tables to the Xen- chosen one which is in actual use by hardware. To read the guest root page table, the directmap is used. PV guests, however, have a directmap which may not cover all memory; in particular this is the case if any memory extends beyond the 5 TiB (CONFIG_BIGMEM=y: 3.5 TiB) address boundary.

SeverityHigh
CVSS8.8
Exploit probability—
Product—
PublishedOct 13, 2026
First seenOct 13, 2026

How to fix

Sources list no fixed version or patch link for this vulnerability.

Affected products

Sources have not yet published the affected products and versions for this vulnerability.

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