{"id":"CVE-2026-79609","published":"2026-10-13T16:17:23.147","lastModified":"2026-10-14T16:10:14.750","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.","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":[],"vendors":[],"products":[],"references":[{"url":"https://xenbits.xenproject.org/xsa/advisory-516.html","tags":[]},{"url":"http://xenbits.xen.org/xsa/advisory-516.html","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}