What is CVE-2021-26409?

CVE-2021-26409 is a high-severity vulnerability in AMD 3rd Gen Epyc, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 7.8/10. Published 2023-01-11.

How severe is CVE-2021-26409?

High severity. CVSS v3 base score is 7.8 out of 10.

Buffer overflow in AMD 3rd Gen Epyc

CVE-2021-26409

Insufficient bounds checking in SEV-ES may allow an attacker to corrupt Reverse Map table (RMP) memory, potentially resulting in a loss of SNP (Secure Nested Paging) memory integrity.

Vulnerability class: Buffer Overflow

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

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.002 (9.2th percentile), scored 2026-11-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 9th percentile — 9.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000

Affected products

Weakness classification (CWE)

CWE-120 — Buffer Copy without Checking Size of Input (Classic Buffer Overflow)

References

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

Frequently asked questions

What is CVE-2021-26409?: CVE-2021-26409 is a high-severity vulnerability in AMD 3rd Gen Epyc, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 7.8/10. Published 2023-01-11.
How severe is CVE-2021-26409?: High severity. CVSS v3 base score is 7.8 out of 10.