HighFix available
xen — security advisory
guests may exceed their designated memory limit When a guest is permitted to have close to 16TiB of memory, it may be able to issue hypercalls to increase its memory allocation beyond the administrator established limit. This is a result of a calculation done with 32-bit precision, which may overflow. It would then only be the overflowed (and hence small) number which gets compared against the established upper bound.
- Products
- xen
- Affected versions
- Not specified
- Fixed versions
- 4.13.4-r2, 4.13.4-r3, 4.14.5-r0, 4.15.2-r0
- CVEs
- CVE-2021-28706
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 22:04 UTC · Revision 1
Source evidence
guests may exceed their designated memory limit When a guest is permitted to have close to 16TiB of memory, it may be able to issue hypercalls to increase its memory allocation beyond the administrator established limit. This is a result of a calculation done with 32-bit precision, which may overflow. It would then only be the overflowed (and hence small) number which gets compared against the established upper bound.
osv:ALPINE-CVE-2021-28706
xen
Fixed versions: 4.13.4-r2
xen
Fixed versions: 4.13.4-r2, 4.13.4-r3
xen
Fixed versions: 4.14.5-r0
xen
Fixed versions: 4.15.2-r0
xen
Fixed versions: 4.15.2-r0
Complete source record
{
"id": "e1c05a685c3119659e4e0742f53f7accc5999bcbcbb276b919288ecf618cc5cf",
"url": "https://osv.dev/vulnerability/ALPINE-CVE-2021-28706",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "ALPINE-CVE-2021-28706",
"summary": "guests may exceed their designated memory limit When a guest is permitted to have close to 16TiB of memory, it may be able to issue hypercalls to increase its memory allocation beyond the administrator established limit. This is a result of a calculation done with 32-bit precision, which may overflow. It would then only be the overflowed (and hence small) number which gets compared against the established upper bound.",
"evidence": "osv:ALPINE-CVE-2021-28706",
"products": [
{
"name": {
"value": "xen",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "4.13.4-r2",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "xen",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "4.13.4-r2",
"evidence": "/affected/1/ranges"
},
{
"value": "4.13.4-r3",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "xen",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "4.14.5-r0",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "xen",
"evidence": "/affected/3/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "4.15.2-r0",
"evidence": "/affected/3/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "xen",
"evidence": "/affected/4/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "4.15.2-r0",
"evidence": "/affected/4/ranges"
}
],
"affected_versions": []
}
],
"severity": "high",
"structured": {
"id": "ALPINE-CVE-2021-28706",
"aliases": [
"ALPINE-CVE-2021-28706"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "3.2"
},
{
"fixed": "4.13.4-r2"
}
]
}
],
"package": {
"name": "xen",
"purl": "pkg:apk/alpine/xen?arch=source",
"ecosystem": "Alpine:v3.11"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-28706.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "3.2"
},
{
"fixed": "4.13.4-r2"
},
{
"fixed": "4.13.4-r3"
}
]
}
],
"package": {
"name": "xen",
"purl": "pkg:apk/alpine/xen?arch=source",
"ecosystem": "Alpine:v3.12"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-28706.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "3.2"
},
{
"fixed": "4.14.5-r0"
}
]
}
],
"package": {
"name": "xen",
"purl": "pkg:apk/alpine/xen?arch=source",
"ecosystem": "Alpine:v3.13"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-28706.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "3.2"
},
{
"fixed": "4.15.2-r0"
}
]
}
],
"package": {
"name": "xen",
"purl": "pkg:apk/alpine/xen?arch=source",
"ecosystem": "Alpine:v3.14"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-28706.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "3.2"
},
{
"fixed": "4.15.2-r0"
}
]
}
],
"package": {
"name": "xen",
"purl": "pkg:apk/alpine/xen?arch=source",
"ecosystem": "Alpine:v3.15"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-28706.json"
},
"ecosystem_specific": {}
}
],
"modified": "2026-10-23T17:17:56.177767386Z",
"provider": "osv",
"upstream": [
"CVE-2021-28706"
],
"references": [
"https://security.alpinelinux.org/vuln/CVE-2021-28706"
]
},
"related_cves": [
{
"value": "CVE-2021-28706",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 415400,
"published_at": "2021-11-24T01:15:08.127+00:00"
}