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01 Record

CVE-2021-26402

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

HighPUBLISHEDCNA: AMD
CNA base score7.1 CVSS v3.xCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

02 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

03 Exploitation and scoring

Exploitation
Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
SSVC decision
  • ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
  • AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
  • Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
EPSS probability
0.18% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 7.6% of scored records. A rank, not a probability.
NVD base score
7.1 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
NVD analysis status
Modified. NVD last modified this record on 2026-06-17.
Red Hat severity
No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2023-01-10 20:56Z3 YR AGO
Last updated
2025-04-08 20:27Z1 YR AGO
Reserved
2021-01-29
Assigning CNA
AMD
Record state
PUBLISHED
Severity
High (CVSS 7.1)
CNA CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
Weaknesses
Data version
5.1
Document digest
e767fa640866e994f0883135498def7c6144fb0f5e0954ba6b3b93411d7e198b

05 Affected products

VendorProductVersionsPlatforms
AMD2nd Gen EPYCVariousx86
AMD3rd Gen EPYCvariousx86

06 References