xen — security advisory
An issue was discovered in Xen through 4.13.x, allowing Arm guest OS users to cause a hypervisor crash because of a missing alignment check in VCPUOP_register_vcpu_info. The hypercall VCPUOP_register_vcpu_info is used by a guest to register a shared region with the hypervisor. The region will be mapped into Xen address space so it can be directly accessed. On Arm, the region is accessed with instructions that require a specific alignment. Unfortunately, there is no check that the address provided by the guest will be correctly aligned. As a result, a malicious guest could cause a hypervisor crash by passing a misaligned address. A malicious guest administrator may cause a hypervisor crash, resulting in a Denial of Service (DoS). All Xen versions are vulnerable. Only Arm systems are vulnerable. x86 systems are not affected.
- Products
- xen
- Affected versions
- Not specified
- Fixed versions
- 4.11.4+24-gddaaccbbab-1
- CVEs
- CVE-2020-15564
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 13:05 UTC · Revision 1
Source evidence
An issue was discovered in Xen through 4.13.x, allowing Arm guest OS users to cause a hypervisor crash because of a missing alignment check in VCPUOP_register_vcpu_info. The hypercall VCPUOP_register_vcpu_info is used by a guest to register a shared region with the hypervisor. The region will be mapped into Xen address space so it can be directly accessed. On Arm, the region is accessed with instructions that require a specific alignment. Unfortunately, there is no check that the address provided by the guest will be correctly aligned. As a result, a malicious guest could cause a hypervisor crash by passing a misaligned address. A malicious guest administrator may cause a hypervisor crash, resulting in a Denial of Service (DoS). All Xen versions are vulnerable. Only Arm systems are vulnerable. x86 systems are not affected.
osv:DEBIAN-CVE-2020-15564
xen
Fixed versions: 4.11.4+24-gddaaccbbab-1
xen
Fixed versions: 4.11.4+24-gddaaccbbab-1
xen
Fixed versions: 4.11.4+24-gddaaccbbab-1
Complete source record
{
"id": "3e35bc37e83f2a9d889581a0de2da71a887ce5565bee6ea7eee71efbffcd94c5",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2020-15564",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2020-15564",
"summary": "An issue was discovered in Xen through 4.13.x, allowing Arm guest OS users to cause a hypervisor crash because of a missing alignment check in VCPUOP_register_vcpu_info. The hypercall VCPUOP_register_vcpu_info is used by a guest to register a shared region with the hypervisor. The region will be mapped into Xen address space so it can be directly accessed. On Arm, the region is accessed with instructions that require a specific alignment. Unfortunately, there is no check that the address provided by the guest will be correctly aligned. As a result, a malicious guest could cause a hypervisor crash by passing a misaligned address. A malicious guest administrator may cause a hypervisor crash, resulting in a Denial of Service (DoS). All Xen versions are vulnerable. Only Arm systems are vulnerable. x86 systems are not affected.",
"evidence": "osv:DEBIAN-CVE-2020-15564",
"products": [
{
"name": {
"value": "xen",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "4.11.4+24-gddaaccbbab-1",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "xen",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "4.11.4+24-gddaaccbbab-1",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "xen",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "4.11.4+24-gddaaccbbab-1",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": []
}
],
"severity": "medium",
"structured": {
"id": "DEBIAN-CVE-2020-15564",
"aliases": [
"DEBIAN-CVE-2020-15564"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "4.11.4+24-gddaaccbbab-1"
}
]
}
],
"package": {
"name": "xen",
"purl": "pkg:deb/debian/xen?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2020-15564.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "4.11.4+24-gddaaccbbab-1"
}
]
}
],
"package": {
"name": "xen",
"purl": "pkg:deb/debian/xen?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2020-15564.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "4.11.4+24-gddaaccbbab-1"
}
]
}
],
"package": {
"name": "xen",
"purl": "pkg:deb/debian/xen?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2020-15564.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-26T12:01:40.196616941Z",
"provider": "osv",
"upstream": [
"CVE-2020-15564"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2020-15564"
]
},
"related_cves": [
{
"value": "CVE-2020-15564",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 451763,
"published_at": "2020-07-07T13:15:10.023+00:00"
}