CVE-2021-26322Network attack vector

Platform-key disclosure via fixed AES-CTR initialization vector

Published Nov 16, 2021 · Updated Sep 17, 2024

Cryptographic weakness in AMD 1st, 2nd, and 3rd Gen EPYC processors allows attackers to recover persistent platform private keys. The ASP persistent-storage export path encrypts different fixed-format state blobs with AES-CTR under the same key and fixed initialization vector, allowing ciphertext pairs to reveal plaintext. The demonstrated recovery requires control of persistent storage and a known plaintext-ciphertext pair, and it exposes confidentiality without altering platform state.

CVSS severity7.5
High
EPSS probability1.05%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cryptographic weakness in AMD 1st, 2nd, and 3rd Gen EPYC processors allows attackers to recover persistent platform private keys. The ASP persistent-storage export path encrypts different fixed-format state blobs with AES-CTR under the same key and fixed initialization vector, allowing ciphertext pairs to reveal plaintext. The demonstrated recovery requires control of persistent storage and a known plaintext-ciphertext pair, and it exposes confidentiality without altering platform state.

The record

CVE
CVE-2021-26322
Published
Nov 16, 2021
Updated
Sep 17, 2024
Vendor
AMD
Product
2nd Gen AMD EPYC Processors
Classifications
CWE-320, T1552.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 16, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <RomePI-SP3_1.0.0.C

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

AMD · 2nd Gen AMD EPYC Processorsversion=unspecified <RomePI-SP3_1.0.0.C
AMD · 3rd Gen AMD EPYC Processorsversion=unspecified <MilanPI-SP3_1.0.0.4
AMD · 1st Gen AMD EPYC Processorsversion=unspecified <NaplesPI-SP3_1.0.0.G

Published CVSS scores

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
5.0NVDAV:N/AC:L/Au:N/C:P/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-320Key Management Errors
T1552.004Unsecured Credentials: Private Keys

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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