{"schema":"threatline.record/2","record":{"id":"CVE-2026-79609","aliases":[],"summary":"x86: XPTI may break on huge-memory systems","details":"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.","categories":["Unclassified"],"product":"Xen","vendor":"Xen","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-79609","source_modified_at":"2026-10-20T17:34:39.462Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Xen","vendor":"Xen","versions":[{"status":"unknown","version":"consult Xen advisory XSA-516"}],"defaultStatus":"unknown"}],"fixed_versions":[],"cvss":8.8,"severity":"High","kev":{"listed":false},"epss":{"probability":0.0011,"percentile":0.0121,"score_date":"2026-10-23"},"published_at":"2026-10-13T15:44:24.763Z","modified_at":"2026-10-20T17:34:39.462Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-79609","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-20T17:34:39.462Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-79609","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://xenbits.xenproject.org/xsa/advisory-516.html"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CISA ADP","ssvc":{"exploitation":"none","automatable":"no","technical_impact":"total","assessed_at":"2026-10-20T17:34:35.122730Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":null,"confidence":"unknown","reviewed":false},"change_timestamp":"2026-10-20T17:34:39.462Z","content_hash":"7ff8f2e1a66385e770e0fbfdb9f54920a8cdb711791776a2163c5db95d595156"}}