HighFix available
xen — security advisory
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.
- Products
- xen
- Affected versions
- 4.17.1+2-gb773c48e36-1, 4.17.2+55-g0b56bed864-1, 4.17.2+76-ge1f9cb16e2-1, 4.17.2+76-ge1f9cb16e2-1~deb12u1, 4.17.2-1, 4.17.3+10-g091466ba55-1, 4.17.3+10-g091466ba55-1.1, 4.17.3+10-g091466ba55-1.1~exp1, 4.17.3+10-g091466ba55-1.1~exp2, 4.17.3+10-g091466ba55-1~deb12u1, 4.17.3+36-g54dacb5c02-1, 4.17.5+23-ga4e5191dc0-1, 4.17.5+23-ga4e5191dc0-1+deb12u1, 4.17.5+72-g01140da4e8-1, 4.17.7-0+deb12u1, 4.19.0+14-g0918434e0f-1~exp1, 4.19.1-1, 4.19.1-1~exp1, 4.19.1-1~exp4, 4.20.0+68-g35cb38b222-1, 4.20.0-1, 4.20.0~rc2+1-gfcde5e0de8-1~exp1, 4.20.2+37-g61ff35323e-0+deb13u1, 4.20.2+37-g61ff35323e-1, 4.20.2+7-g1badcf5035-0+deb13u1, 4.20.2+7-g1badcf5035-1, 4.20.2+7-g1badcf5035-2, 4.20.3+127-gc42374a105-0+deb13u1, 4.20.3+127-gc42374a105-1, 4.20.4+39-gf1e1321c87-1
- Fixed versions
- 4.20.4+39-gf1e1321c87-0+deb13u1, 4.20.4+39-gf1e1321c87-1
- CVEs
- CVE-2026-79609
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 02:20 UTC · Revision 1
Source evidence
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.
osv:DEBIAN-CVE-2026-79609
xen
Fixed versions: Not specified
xen
Fixed versions: 4.20.4+39-gf1e1321c87-0+deb13u1
xen
Fixed versions: 4.20.4+39-gf1e1321c87-1
Complete source record
{
"id": "eab09fb5a1dc6caef1fb15e8358bd7a301429f50d3244fffab9eee627b9f0c28",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-79609",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-79609",
"summary": "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.",
"evidence": "osv:DEBIAN-CVE-2026-79609",
"products": [
{
"name": {
"value": "xen",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "4.17.1+2-gb773c48e36-1",
"evidence": "/affected/0/versions"
},
{
"value": "4.17.2+55-g0b56bed864-1",
"evidence": "/affected/0/versions"
},
{
"value": "4.17.2+76-ge1f9cb16e2-1",
"evidence": "/affected/0/versions"
},
{
"value": "4.17.2+76-ge1f9cb16e2-1~deb12u1",
"evidence": "/affected/0/versions"
},
{
"value": "4.17.2-1",
"evidence": "/affected/0/versions"
},
{
"value": "4.17.3+10-g091466ba55-1",
"evidence": "/affected/0/versions"
},
{
"value": "4.17.3+10-g091466ba55-1.1",
"evidence": "/affected/0/versions"
},
{
"value": "4.17.3+10-g091466ba55-1.1~exp1",
"evidence": "/affected/0/versions"
},
{
"value": "4.17.3+10-g091466ba55-1.1~exp2",
"evidence": "/affected/0/versions"
},
{
"value": "4.17.3+10-g091466ba55-1~deb12u1",
"evidence": "/affected/0/versions"
},
{
"value": "4.17.3+36-g54dacb5c02-1",
"evidence": "/affected/0/versions"
},
{
"value": "4.17.5+23-ga4e5191dc0-1",
"evidence": "/affected/0/versions"
},
{
"value": "4.17.5+23-ga4e5191dc0-1+deb12u1",
"evidence": "/affected/0/versions"
},
{
"value": "4.17.5+72-g01140da4e8-1",
"evidence": "/affected/0/versions"
},
{
"value": "4.17.7-0+deb12u1",
"evidence": "/affected/0/versions"
},
{
"value": "4.19.0+14-g0918434e0f-1~exp1",
"evidence": "/affected/0/versions"
},
{
"value": "4.19.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "4.19.1-1~exp1",
"evidence": "/affected/0/versions"
},
{
"value": "4.19.1-1~exp4",
"evidence": "/affected/0/versions"
},
{
"value": "4.20.0+68-g35cb38b222-1",
"evidence": "/affected/0/versions"
},
{
"value": "4.20.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "4.20.0~rc2+1-gfcde5e0de8-1~exp1",
"evidence": "/affected/0/versions"
},
{
"value": "4.20.2+37-g61ff35323e-1",
"evidence": "/affected/0/versions"
},
{
"value": "4.20.2+7-g1badcf5035-1",
"evidence": "/affected/0/versions"
},
{
"value": "4.20.2+7-g1badcf5035-2",
"evidence": "/affected/0/versions"
},
{
"value": "4.20.3+127-gc42374a105-1",
"evidence": "/affected/0/versions"
},
{
"value": "4.20.4+39-gf1e1321c87-1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "xen",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "4.20.4+39-gf1e1321c87-0+deb13u1",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": [
{
"value": "4.20.0+68-g35cb38b222-1",
"evidence": "/affected/1/versions"
},
{
"value": "4.20.2+37-g61ff35323e-0+deb13u1",
"evidence": "/affected/1/versions"
},
{
"value": "4.20.2+37-g61ff35323e-1",
"evidence": "/affected/1/versions"
},
{
"value": "4.20.2+7-g1badcf5035-0+deb13u1",
"evidence": "/affected/1/versions"
},
{
"value": "4.20.2+7-g1badcf5035-1",
"evidence": "/affected/1/versions"
},
{
"value": "4.20.2+7-g1badcf5035-2",
"evidence": "/affected/1/versions"
},
{
"value": "4.20.3+127-gc42374a105-0+deb13u1",
"evidence": "/affected/1/versions"
},
{
"value": "4.20.3+127-gc42374a105-1",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "xen",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "4.20.4+39-gf1e1321c87-1",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": [
{
"value": "4.20.0+68-g35cb38b222-1",
"evidence": "/affected/2/versions"
},
{
"value": "4.20.2+37-g61ff35323e-1",
"evidence": "/affected/2/versions"
},
{
"value": "4.20.2+7-g1badcf5035-1",
"evidence": "/affected/2/versions"
},
{
"value": "4.20.2+7-g1badcf5035-2",
"evidence": "/affected/2/versions"
},
{
"value": "4.20.3+127-gc42374a105-1",
"evidence": "/affected/2/versions"
}
]
}
],
"severity": "high",
"structured": {
"id": "DEBIAN-CVE-2026-79609",
"aliases": [
"DEBIAN-CVE-2026-79609"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "xen",
"purl": "pkg:deb/debian/xen?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"4.17.1+2-gb773c48e36-1",
"4.17.2+55-g0b56bed864-1",
"4.17.2+76-ge1f9cb16e2-1",
"4.17.2+76-ge1f9cb16e2-1~deb12u1",
"4.17.2-1",
"4.17.3+10-g091466ba55-1",
"4.17.3+10-g091466ba55-1.1",
"4.17.3+10-g091466ba55-1.1~exp1",
"4.17.3+10-g091466ba55-1.1~exp2",
"4.17.3+10-g091466ba55-1~deb12u1",
"4.17.3+36-g54dacb5c02-1",
"4.17.5+23-ga4e5191dc0-1",
"4.17.5+23-ga4e5191dc0-1+deb12u1",
"4.17.5+72-g01140da4e8-1",
"4.17.7-0+deb12u1",
"4.19.0+14-g0918434e0f-1~exp1",
"4.19.1-1",
"4.19.1-1~exp1",
"4.19.1-1~exp4",
"4.20.0+68-g35cb38b222-1",
"4.20.0-1",
"4.20.0~rc2+1-gfcde5e0de8-1~exp1",
"4.20.2+37-g61ff35323e-1",
"4.20.2+7-g1badcf5035-1",
"4.20.2+7-g1badcf5035-2",
"4.20.3+127-gc42374a105-1",
"4.20.4+39-gf1e1321c87-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-79609.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "4.20.4+39-gf1e1321c87-0+deb13u1"
}
]
}
],
"package": {
"name": "xen",
"purl": "pkg:deb/debian/xen?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"4.20.0+68-g35cb38b222-1",
"4.20.2+37-g61ff35323e-0+deb13u1",
"4.20.2+37-g61ff35323e-1",
"4.20.2+7-g1badcf5035-0+deb13u1",
"4.20.2+7-g1badcf5035-1",
"4.20.2+7-g1badcf5035-2",
"4.20.3+127-gc42374a105-0+deb13u1",
"4.20.3+127-gc42374a105-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-79609.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "4.20.4+39-gf1e1321c87-1"
}
]
}
],
"package": {
"name": "xen",
"purl": "pkg:deb/debian/xen?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"4.20.0+68-g35cb38b222-1",
"4.20.2+37-g61ff35323e-1",
"4.20.2+7-g1badcf5035-1",
"4.20.2+7-g1badcf5035-2",
"4.20.3+127-gc42374a105-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-79609.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-23T18:05:44.816554955Z",
"provider": "osv",
"upstream": [
"CVE-2026-79609"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-79609"
]
},
"related_cves": [
{
"value": "CVE-2026-79609",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 424558,
"published_at": "2026-10-13T16:17:23.147+00:00"
}