CVE-2021-26402: amd 2nd gen epyc Out-of-bounds Write
CVSS: 7.1v3.1HighModified
Published 10-01-2023Last modified 08-04-2025
Vulnerability summary
CVE-2021-26402 is a high (CVSS 7.1) Out-of-bounds Write vulnerability in amd 2nd gen epyc. EPSS estimates a 0.18% chance of exploitation in the next 30 days, higher than 7% of scored vulnerabilities.
CVSS score
7.1/10
010
High · v3.1 (CVE.org)EPSS score
0.18%
0%100%
Low · 0.00 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Timeline
- 10-01-2023PublishedVulnerability first disclosed.
- 08-04-2025Last modifiedVulnerability information updated.
Description
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.
CVSS metrics
2 scores · 2 sources · 1 versionHigh 7.1Preferred score · CVE.org (CNA)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:HSourcesAll 2 agree
- NVDNIST7.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
EPSS trend
Probability
0.18%
Chance of exploitation in the next 30 days
Percentile
7%
Versus all other CVEs
30-day change
0.00 pp
From 0.18% on 19-09-2026
19-09-202619-10-2026
EPSS score0.18%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Amd52 products
- 2nd gen epycVarious
- 3rd gen epycvarious
- epyc_7002_firmware< romepi_1.0.0.c
- epyc_7003_firmware< milanpi_1.0.0.4
- epyc_7232p_firmware< romepi_1.0.0.c
1 vendor · 52 products