CVE-2021-26402

Insufficient bounds checking in ASP (AMD Secure Processor) firmware while handling BIOS mailbox...

7.1 High

Insufficient bounds checking in ASP (AMD Secure Processor) firmware while handling BIOS mailbox commands, may allow an attacker to write partially-controlled data out-of-bounds to SMM or SEV-ES regions which may lead to a potential loss of integrity and availability.

Attack profile

How easy it is to exploit

Attack vector: Local
Complexity: Low
Privileges needed: Low
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: High
Availability: High

Exploit likelihood

0.18%Down 0.7 points since Jan 11, 2023

What each source reports

NVD Score used 7.1

Record: CVE-2021-26402
CVSS 3.1: 7.1 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
Weakness: CWE-787
Updated: 2026-11-02

CVE List 7.1

Record: CVE-2021-26402
CVSS 3.1: 7.1 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
Weakness: CWE-787
Updated: 2026-11-02

EUVDEUVD-2021-13208 7.1

Record: EUVD-2021-13208
CVSS 3.1: 7.1 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
Updated: 2026-11-02

GitHub AdvisoriesGHSA-f358-f8cc-67vr 7.1

Insufficient bounds checking in ASP (AMD Secure Processor) firmware while handling BIOS mailbox...

Record: GHSA-f358-f8cc-67vr
CVSS 3.1: 7.1 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
Weakness: CWE-787
Updated: 2026-11-02

Affected products

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History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-26402 is a high vulnerability (CVSS 7.1) in Amd 2nd Gen Epyc, published January 10, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.18%, the 8th percentile. No source names a fixed version.