{"id":"CVE-2026-79609","revision":"55aecef70b4644c5a5751737dc0ad43c","records":[{"revision":"55aecef70b4644c5a5751737dc0ad43c","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-79609","aliases":[],"title":"x86: XPTI may break on huge-memory systems","description":"XPTI (Xen Page Table Isolation) was introduced to mitigate Meltdown\n(CVE-2017-5754, one aspect of XSA-254).  This involves copying 64-bit PV\nguest page table entries from guest-chosen root page tables to the Xen-\nchosen one which is in actual use by hardware.  To read the guest root\npage table, the directmap is used.  PV guests, however, have a directmap\nwhich may not cover all memory; in particular this is the case if any\nmemory extends beyond the 5 TiB (CONFIG_BIGMEM=y: 3.5 TiB) address\nboundary.","state":0,"publishedAt":"2026-10-13T15:44:24.763+00:00","modifiedAt":"2026-10-20T17:34:39.462+00:00","affected":[{"ecosystem":"Vendor product","name":"Xen","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"defaultStatus\": \"unknown\",\n                    \"product\": \"Xen\",\n                    \"vendor\": \"Xen\",\n                    \"versions\": [\n                        {\n                            \"status\": \"unknown\",\n                            \"version\": \"consult Xen advisory XSA-516\"\n                        }\n                    ]\n                }"}],"metrics":[],"references":["https://xenbits.xenproject.org/xsa/advisory-516.html"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-79609","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-79609","identifiers":["CVE-2026-79609"]},"retained":false,"historicalAffected":[]}],"coverage":[]}