What is CVE-2021-26396?

CVE-2021-26396 is a medium-severity vulnerability in AMD 3rd Gen Epyc, classified under Insufficient Verification of Data Authenticity. CVSS score: 4.4/10. Published 2023-01-11.

How severe is CVE-2021-26396?

Medium severity. CVSS v3 base score is 4.4 out of 10.

Vulnerability in AMD 3rd Gen Epyc

CVE-2021-26396

Insufficient validation of address mapping to IO in ASP (AMD Secure Processor) may result in a loss of memory integrity in the SNP guest.

Published 2023-01-11 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.4 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L.

EPSS exploit prediction

EPSS: 0.001 (1.3th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 1st percentile — 1.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: 0.000

Affected products

Weakness classification (CWE)

CWE-345 — Insufficient Verification of Data Authenticity

References

www.amd.com/en/corporate/product-security/bulletin/AMD-SB-1032 (vendor-advisory, Vendor Advisory)

Frequently asked questions

What is CVE-2021-26396?: CVE-2021-26396 is a medium-severity vulnerability in AMD 3rd Gen Epyc, classified under Insufficient Verification of Data Authenticity. CVSS score: 4.4/10. Published 2023-01-11.
How severe is CVE-2021-26396?: Medium severity. CVSS v3 base score is 4.4 out of 10.