xen — security advisory
Mishandling of guest SSBD selection on AMD hardware The current logic to set SSBD on AMD Family 17h and Hygon Family 18h processors requires that the setting of SSBD is coordinated at a core level, as the setting is shared between threads. Logic was introduced to keep track of how many threads require SSBD active in order to coordinate it, such logic relies on using a per-core counter of threads that have SSBD active. When running on the mentioned hardware, it's possible for a guest to under or overflow the thread counter, because each write to VIRT_SPEC_CTRL.SSBD by the guest gets propagated to the helper that does the per-core active accounting. Underflowing the counter causes the value to get saturated, and thus attempts for guests running on the same core to set SSBD won't have effect because the hypervisor assumes it's already active.
- Products
- xen
- Affected versions
- Not specified
- Fixed versions
- 4.17.1-r1
- CVEs
- CVE-2022-42336
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 30 Oct 2026, 14:19 UTC · Revision 1
Source evidence
Mishandling of guest SSBD selection on AMD hardware The current logic to set SSBD on AMD Family 17h and Hygon Family 18h processors requires that the setting of SSBD is coordinated at a core level, as the setting is shared between threads. Logic was introduced to keep track of how many threads require SSBD active in order to coordinate it, such logic relies on using a per-core counter of threads that have SSBD active. When running on the mentioned hardware, it's possible for a guest to under or overflow the thread counter, because each write to VIRT_SPEC_CTRL.SSBD by the guest gets propagated to the helper that does the per-core active accounting. Underflowing the counter causes the value to get saturated, and thus attempts for guests running on the same core to set SSBD won't have effect because the hypervisor assumes it's already active.
osv:ALPINE-CVE-2022-42336
xen
Fixed versions: 4.17.1-r1
xen
Fixed versions: 4.17.1-r1
xen
Fixed versions: 4.17.1-r1
xen
Fixed versions: 4.17.1-r1
xen
Fixed versions: 4.17.1-r1
xen
Fixed versions: 4.17.1-r1
xen
Fixed versions: 4.17.1-r1
Complete source record
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"id": "16de6647d84a78e103bc201c10f397d533356c2f9307295d02e010850f0c3943",
"url": "https://osv.dev/vulnerability/ALPINE-CVE-2022-42336",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "ALPINE-CVE-2022-42336",
"summary": "Mishandling of guest SSBD selection on AMD hardware The current logic to set SSBD on AMD Family 17h and Hygon Family 18h processors requires that the setting of SSBD is coordinated at a core level, as the setting is shared between threads. Logic was introduced to keep track of how many threads require SSBD active in order to coordinate it, such logic relies on using a per-core counter of threads that have SSBD active. When running on the mentioned hardware, it's possible for a guest to under or overflow the thread counter, because each write to VIRT_SPEC_CTRL.SSBD by the guest gets propagated to the helper that does the per-core active accounting. Underflowing the counter causes the value to get saturated, and thus attempts for guests running on the same core to set SSBD won't have effect because the hypervisor assumes it's already active.",
"evidence": "osv:ALPINE-CVE-2022-42336",
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"evidence": "/affected/0/package/name"
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"severity": "low",
"structured": {
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"aliases": [
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"metrics": [
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"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N"
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],
"modified": "2026-10-15T07:17:54.269245503Z",
"provider": "osv",
"upstream": [
"CVE-2022-42336"
],
"references": [
"https://security.alpinelinux.org/vuln/CVE-2022-42336"
]
},
"related_cves": [
{
"value": "CVE-2022-42336",
"evidence": "/upstream"
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],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 322024,
"published_at": "2023-05-17T01:15:09.48+00:00"
}