CVE-2026-79609
x86: XPTI may break on huge-memory systems
- State
- Published
- Severity
- 8.8 High
- Published
- Oct 13, 2026
- Updated
- Oct 20, 2026
- Reserved
- Aug 25, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 8.8 High | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H | CISA-ADP |
Weaknesses
- CWE-284 Improper Access Control
Affected Products
| Product | Versions |
|---|---|
XenXen |
|
References
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