Vulnerability 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 Score
LOW
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Xen | Xen | 4.17 |
References
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://xenbits.xenproject.org/xsa/advisory-431.txtVendor Advisory
- http://xenbits.xen.org/xsa/advisory-431.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://xenbits.xenproject.org/xsa/advisory-431.txtVendor Advisory
FAQ
What is CVE-2022-42336?
CVE-2022-42336 is a vulnerability with a CVSS score of 3.3 (LOW). 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...
How severe is CVE-2022-42336?
CVE-2022-42336 has been rated LOW with a CVSS base score of 3.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2022-42336?
Check the references section above for vendor advisories and patch information. Affected products include: Xen Xen.