{"cve":"CVE-2022-42336","nvd":{"published":"2023-05-17T01:15:09.480","modified":"2026-06-17T05:04:45.170","status":"Modified","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","score":3.3},"cwes":[],"references":["https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LTO3U3WYLAZW3KLPKJZ332FYUREXPZMQ/","https://xenbits.xenproject.org/xsa/advisory-431.txt","http://xenbits.xen.org/xsa/advisory-431.html","https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LTO3U3WYLAZW3KLPKJZ332FYUREXPZMQ/","https://xenbits.xenproject.org/xsa/advisory-431.txt"],"products":["xen:xen"],"source":"nvd","synced_at":"2026-10-19T21:38:18.424950729+00:00"},"epss":{"cve":"CVE-2022-42336","score":0.00266,"percentile":0.18575,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}