CVE-2021-26342

Name: CVE-2021-26342
Creator: NVD / NIST
Published: 2022-05-11T17:15:08.297+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

LOWCVSS 3.3/10EPSS 0.21%

Last modified Jun 17, 2026

CVE-2021-26342 is a low-severity vulnerability rated 3.3/10 on the CVSS scale. 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. EPSS estimates a 0.21% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

3.3/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

EPSS Probability

0.21%

11.8th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Amd	Epyc 7763 Firmware	< milanpi-sp3_1.0.0.7
Amd	Epyc 7713p Firmware	< milanpi-sp3_1.0.0.7
Amd	Epyc 7713 Firmware	< milanpi-sp3_1.0.0.7
Amd	Epyc 7663 Firmware	< milanpi-sp3_1.0.0.7
Amd	Epyc 7643 Firmware	< milanpi-sp3_1.0.0.7
Amd	Epyc 75f3 Firmware	< milanpi-sp3_1.0.0.7
Amd	Epyc 7543p Firmware	< milanpi-sp3_1.0.0.7
Amd	Epyc 7543 Firmware	< milanpi-sp3_1.0.0.7
Amd	Epyc 7513 Firmware	< milanpi-sp3_1.0.0.7
Amd	Epyc 7453 Firmware	< milanpi-sp3_1.0.0.7
Amd	Epyc 74f3 Firmware	< milanpi-sp3_1.0.0.7
Amd	Epyc 7443p Firmware	< milanpi-sp3_1.0.0.7
Amd	Epyc 7443 Firmware	< milanpi-sp3_1.0.0.7
Amd	Epyc 7413 Firmware	< milanpi-sp3_1.0.0.7
Amd	Epyc 73f3 Firmware	< milanpi-sp3_1.0.0.7
Amd	Epyc 7343 Firmware	< milanpi-sp3_1.0.0.7
Amd	Epyc 7313p Firmware	< milanpi-sp3_1.0.0.7
Amd	Epyc 7313 Firmware	< milanpi-sp3_1.0.0.7
Amd	Epyc 72f3 Firmware	< milanpi-sp3_1.0.0.7
Amd	Epyc 7773x Firmware	< milanpi-sp3_1.0.0.7
Amd	Epyc 7473x Firmware	< milanpi-sp3_1.0.0.7
Amd	Epyc 7573x Firmware	< milanpi-sp3_1.0.0.7
Amd	Epyc 7373x Firmware	< milanpi-sp3_1.0.0.7
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 7301 Firmware	< naplespi-sp3_1.0.0.h
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
Amd	Epyc 7401 Firmware	< naplespi-sp3_1.0.0.h
Amd	Epyc 7401p Firmware	< naplespi-sp3_1.0.0.h
Amd	Epyc 7451 Firmware	< naplespi-sp3_1.0.0.h
Amd	Epyc 7501 Firmware	< naplespi-sp3_1.0.0.h
Amd	Epyc 7551 Firmware	< naplespi-sp3_1.0.0.h
Amd	Epyc 7551p Firmware	< naplespi-sp3_1.0.0.h
Amd	Epyc 7601 Firmware	< naplespi-sp3_1.0.0.h

References

https://www.amd.com/en/corporate/product-security/bulletin/amd-sb-1028Vendor Advisory
https://www.amd.com/en/corporate/product-security/bulletin/amd-sb-1028Vendor Advisory

Timeline

Published: May 11, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-26342?

How severe is CVE-2021-26342?

CVE-2021-26342 has a CVSS score of 3.3/10 (LOW severity). The EPSS model estimates a 0.21% probability of exploitation in the next 30 days.

How do I fix CVE-2021-26342?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-26342?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST