CVE-2021-26409 Memory corruption in 3rd Gen EPYC

High 7.8 Published 10 Jan 2023 Updated 9 Apr 2025

Insufficient bounds checking in AMD SEV-ES allows attackers to corrupt Reverse Map table memory, compromising Secure Nested Paging integrity.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: Not needed
Fix: None listed

What is CVE-2021-26409?

CVE-2021-26409 is a high-severity memory corruption vulnerability in AMD 3rd Gen EPYC, published on 10 Jan 2023. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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.

Weakness: CWE-120

Which versions are affected by CVE-2021-26409?

It affects 1 product.

Products include Amd Milanpi Firmware.

How do I fix CVE-2021-26409?

No fix has been published for CVE-2021-26409 yet. Limit exposure of the affected software until one is available.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2021-26409 being exploited?

There is no known exploitation of CVE-2021-26409 in the wild and no public exploit code.

Sources

Also known as GHSA-53r6-9q9v-359p.