Cyber Resilience

CVE-2023-20521

Race Condition in Amd Epyc 7001 Firmware ≤ naplespi_1.0.0.h

Race Condition
Published
14 November 2023
Modified
21 November 2024
Patch / advisory
View advisory
CVSS Score v3.1 3.3
Click a component to see what it means
Raw vectorCVSS:3.1/AV:P/AC:H/PR:H/UI:N/S:C/C:L/I:N/A:L
EPSS Score 0.0026 17th percentile
Risk Priority 26 floored blend · peak EPSS

Summary

CVE-2023-20521 is a low-severity Time-of-check Time-of-use (TOCTOU) Race Condition (CWE-367) vulnerability in Amd Epyc 7001 Firmware. Its CVSS base score is 3.3 (Low).

Operationally, exploitation aligns with the MITRE ATT&CK technique Path Interception (T1034); ranked at the 17th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability Data

TOCTOU in the ASP Bootloader may allow an attacker with physical access to tamper with SPI ROM records after memory content verification, potentially leading to loss of confidentiality or a denial of service.

CWE(s)
CWE-367

Related Threats

MITRE ATT&CK Enterprise Techniques

T1034 Path Interception Persistence
**This technique has been deprecated.
attack.mitre.org →
T1548 Abuse Elevation Control Mechanism Privilege Escalation
Adversaries may circumvent mechanisms designed to control privilege elevation to gain higher-level permissions.
attack.mitre.org →
T1574 Hijack Execution Flow Stealth
Adversaries may execute their own malicious payloads by hijacking the way operating systems run programs.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-20578Same product: Amd Epyc 7001
CVE-2023-20523Same product: Amd Epyc 7232P
CVE-2023-20548Same vendor: Amd
CVE-2023-31324Same vendor: Amd
CVE-2023-20526Same product: Amd Epyc 7001
CVE-2023-20592Same product: Amd Epyc 7001
CVE-2023-20520Same product: Amd Epyc 7232P
CVE-2023-20527Same product: Amd Epyc 7001
CVE-2023-20524Same product: Amd Epyc 7232P
CVE-2023-20529Same product: Amd Epyc 7232P

Affected Assets

amd
epyc 7001 firmware
≤ naplespi_1.0.0.h
amd
epyc 7251 firmware
≤ naplespi_1.0.0.h
amd
epyc 7261 firmware
≤ naplespi_1.0.0.h
amd
epyc 7281 firmware
≤ naplespi_1.0.0.h
amd
epyc 7301 firmware
≤ naplespi_1.0.0.h
amd
epyc 7351 firmware
≤ naplespi_1.0.0.h
amd
epyc 7351p firmware
≤ naplespi_1.0.0.h
amd
epyc 7371 firmware
≤ naplespi_1.0.0.h
amd
epyc 7401 firmware
≤ naplespi_1.0.0.h
amd
epyc 7401p firmware
≤ naplespi_1.0.0.h
+83 more product configuration(s) — see NVD for full list

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V15.4.2
  • V17.2.6

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

AU-8 Time Stamps
addresses: CWE-367

Timestamps meeting UTC or offset standards help identify TOCTOU issues through precise chronological reconstruction of check/use operations.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly include coding standards and reviews that prevent TOCTOU race conditions.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.17 Clock synchronization none match
none

Reliable, synchronized time across systems narrows the exploitable window in which a resource state can change between a security check and its use.

References