Intel processors (shared buffers data sampling): Incomplete cleanup of microarchitectural fill buffers lets a local

CVSS 5.5CVE-2022-21125Firmware, BMC & network fabricSBDSMMIO Stale Datacurated

Impact

Incomplete cleanup of microarchitectural fill buffers lets a local user sample data left behind by other contexts. Part of the MMIO stale-data cluster, whose distinguishing feature is that a guest can pull data across the VM boundary through device MMIO accesses - relevant on any node passing devices through to tenants, which describes every GPU node.

Who can reach it

Local authenticated code, including inside a guest with a passed-through device.

What to do

Mitigated by an Intel microcode update plus OS/hypervisor changes. Microcode for this class is normally shipped by your distribution as an early-loadable image, so you can deploy it with a package update and a reboot without waiting for an OEM BIOS release - that distinction is the difference between a week and a quarter. Verify after reboot by reading /sys/devices/system/cpu/vulnerabilities/ rather than assuming the package took effect. The hypervisor half of the mitigation matters here: make sure your VMM's stale-data mitigations are enabled, not just the host microcode. On nodes that host untrusted co-tenants, also disable SMT or enforce core scheduling; that costs real throughput and is a capacity-planning decision, not a free toggle.

References

https://nvd.nist.gov/vuln/detail/CVE-2022-21125 https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00615.html

This entry is curated: imported from vendor advisories with machine assistance, not yet individually verified. Confirm against your vendor's advisory before acting, and report anything wrong.