What is CVE-2023-20523?

CVE-2023-20523 is a medium-severity vulnerability in AMD 2nd Gen Epyc, classified under Time-of-check Time-of-use (TOCTOU) Race Condition. CVSS score: 5.7/10. Published 2023-01-11.

How severe is CVE-2023-20523?

Medium severity. CVSS v3 base score is 5.7 out of 10.

Vulnerability in AMD 2nd Gen Epyc

CVE-2023-20523

TOCTOU in the ASP may allow a physical attacker to write beyond the buffer bounds, potentially leading to a loss of integrity or denial of service.

Vulnerability class: TOCTOU (Time-of-Check to Time-of-Use)

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

CVSS v3 metric

CVSS v3 base score 5.7 (Medium). Vector: CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H.

EPSS exploit prediction

EPSS: 0.002 (8.0th percentile), scored 2026-11-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 8th percentile — 8.0% 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-367 — Time-of-check Time-of-use (TOCTOU) Race Condition

References

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

Frequently asked questions

What is CVE-2023-20523?: CVE-2023-20523 is a medium-severity vulnerability in AMD 2nd Gen Epyc, classified under Time-of-check Time-of-use (TOCTOU) Race Condition. CVSS score: 5.7/10. Published 2023-01-11.
How severe is CVE-2023-20523?: Medium severity. CVSS v3 base score is 5.7 out of 10.