CVE-2021-26342

Severity: low (CVSS 3.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2022-05-11 · updated 2026-06-17

Description

In SEV guest VMs, the CPU may fail to flush the Translation Lookaside Buffer (TLB) following a particular sequence of operations that includes creation of a new virtual machine control block (VMCB). The failure to flush the TLB may cause the microcode to use stale TLB translations which may allow for disclosure of SEV guest memory contents. Users of SEV-ES/SEV-SNP guest VMs are not impacted by this vulnerability.

Affected products

AMD Epyc 7001 Firmware: before naplespi-sp3_1.0.0.h — fixed in naplespi-sp3_1.0.0.h
AMD Epyc 7251 Firmware: before naplespi-sp3_1.0.0.h — fixed in naplespi-sp3_1.0.0.h
AMD Epyc 7261 Firmware: before naplespi-sp3_1.0.0.h — fixed in naplespi-sp3_1.0.0.h
AMD Epyc 7281 Firmware: before naplespi-sp3_1.0.0.h — fixed in naplespi-sp3_1.0.0.h
AMD Epyc 72F3 Firmware: before milanpi-sp3_1.0.0.7 — fixed in milanpi-sp3_1.0.0.7
AMD Epyc 7301 Firmware: before naplespi-sp3_1.0.0.h — fixed in naplespi-sp3_1.0.0.h
AMD Epyc 7313 Firmware: before milanpi-sp3_1.0.0.7 — fixed in milanpi-sp3_1.0.0.7
AMD Epyc 7313P Firmware: before milanpi-sp3_1.0.0.7 — fixed in milanpi-sp3_1.0.0.7
AMD Epyc 7343 Firmware: before milanpi-sp3_1.0.0.7 — fixed in milanpi-sp3_1.0.0.7
AMD Epyc 7351 Firmware: before naplespi-sp3_1.0.0.h — fixed in naplespi-sp3_1.0.0.h
AMD Epyc 7351P Firmware: before naplespi-sp3_1.0.0.h — fixed in naplespi-sp3_1.0.0.h
AMD Epyc 7371 Firmware: before naplespi-sp3_1.0.0.h — fixed in naplespi-sp3_1.0.0.h
AMD Epyc 7373X Firmware: before milanpi-sp3_1.0.0.7 — fixed in milanpi-sp3_1.0.0.7
AMD Epyc 73F3 Firmware: before milanpi-sp3_1.0.0.7 — fixed in milanpi-sp3_1.0.0.7
AMD Epyc 7401 Firmware: before naplespi-sp3_1.0.0.h — fixed in naplespi-sp3_1.0.0.h
AMD Epyc 7401P Firmware: before naplespi-sp3_1.0.0.h — fixed in naplespi-sp3_1.0.0.h
AMD Epyc 7413 Firmware: before milanpi-sp3_1.0.0.7 — fixed in milanpi-sp3_1.0.0.7
AMD Epyc 7443 Firmware: before milanpi-sp3_1.0.0.7 — fixed in milanpi-sp3_1.0.0.7
AMD Epyc 7443P Firmware: before milanpi-sp3_1.0.0.7 — fixed in milanpi-sp3_1.0.0.7
AMD Epyc 7451 Firmware: before naplespi-sp3_1.0.0.h — fixed in naplespi-sp3_1.0.0.h
AMD Epyc 7453 Firmware: before milanpi-sp3_1.0.0.7 — fixed in milanpi-sp3_1.0.0.7
AMD Epyc 7473X Firmware: before milanpi-sp3_1.0.0.7 — fixed in milanpi-sp3_1.0.0.7
AMD Epyc 74F3 Firmware: before milanpi-sp3_1.0.0.7 — fixed in milanpi-sp3_1.0.0.7
AMD Epyc 7501 Firmware: before naplespi-sp3_1.0.0.h — fixed in naplespi-sp3_1.0.0.h
AMD Epyc 7513 Firmware: before milanpi-sp3_1.0.0.7 — fixed in milanpi-sp3_1.0.0.7
AMD Epyc 7543 Firmware: before milanpi-sp3_1.0.0.7 — fixed in milanpi-sp3_1.0.0.7
AMD Epyc 7543P Firmware: before milanpi-sp3_1.0.0.7 — fixed in milanpi-sp3_1.0.0.7
AMD Epyc 7551 Firmware: before naplespi-sp3_1.0.0.h — fixed in naplespi-sp3_1.0.0.h
AMD Epyc 7551P Firmware: before naplespi-sp3_1.0.0.h — fixed in naplespi-sp3_1.0.0.h
AMD Epyc 7573X Firmware: before milanpi-sp3_1.0.0.7 — fixed in milanpi-sp3_1.0.0.7

How to fix

Upgrade to a fixed version: AMD Epyc 7001 Firmware naplespi-sp3_1.0.0.h; AMD Epyc 7251 Firmware naplespi-sp3_1.0.0.h; AMD Epyc 7261 Firmware naplespi-sp3_1.0.0.h; AMD Epyc 7281 Firmware naplespi-sp3_1.0.0.h; AMD Epyc 72F3 Firmware milanpi-sp3_1.0.0.7; AMD Epyc 7301 Firmware naplespi-sp3_1.0.0.h; AMD Epyc 7313 Firmware milanpi-sp3_1.0.0.7; AMD Epyc 7313P Firmware milanpi-sp3_1.0.0.7; AMD Epyc 7343 Firmware milanpi-sp3_1.0.0.7; AMD Epyc 7351 Firmware naplespi-sp3_1.0.0.h; AMD Epyc 7351P Firmware naplespi-sp3_1.0.0.h; AMD Epyc 7371 Firmware naplespi-sp3_1.0.0.h. Check the vendor advisory for mitigations.

References

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