https://seclists.org/oss-sec/2026/q4/144: Xen Security Advisory 516 v2 (CVE-2026-79609) - x86: XPTI may bak on huge-memory systems
Published Oct 13, 2026
·Updated
Affected Software
1 affected component
Xen Project Xen>=4.7.5, >=4.8.3, >=4.9.2, >=4.10.1, >=4.11
Frequently Asked Questions
1
Which guest types can exploit this issue?
The issue affects 64-bit PV guests. A vulnerable guest may be able to gain host-level privileges, access information relating to other guests, or trigger host-wide denial of service.
2
What host memory configuration makes the condition relevant?
The problematic condition occurs when guest memory extends beyond the directmap coverage boundary: 5 TiB, or 3.5 TiB when CONFIG_BIGMEM=y. In that situation, the PV guest directmap may not cover all memory needed by XPTI.
3
Which Xen releases are affected?
All Xen versions to which the XPTI work was backported are affected. Upstream affected releases include Xen 4.7.5 and later, 4.8.3 and later, 4.9.2 and later, and 4.10.1 and later.