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Fencer Vulns
high 7.1

CVE-2021-26402 json

Insufficient bounds checking in ASP (AMD Secure Processor) firmware while handling BIOS mailbox commands, may allow an attacker to write pa…

published 2023-01-10 3 y ago modified 2026-06-17 4 mo ago also EUVD-2021-13208

cvss
7.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 8%
public exploits
0
none known

Summary

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.

Patch / fix

  • amd epyc_7h12_firmware romepi_1.0.0.c
  • amd epyc_7f72_firmware romepi_1.0.0.c
  • amd epyc_7f52_firmware romepi_1.0.0.c
  • amd epyc_7f32_firmware romepi_1.0.0.c
  • amd epyc_7742_firmware romepi_1.0.0.c
  • amd epyc_7702p_firmware romepi_1.0.0.c
  • amd epyc_7702_firmware romepi_1.0.0.c
  • amd epyc_7662_firmware romepi_1.0.0.c
  • amd epyc_7642_firmware romepi_1.0.0.c
  • amd epyc_7552_firmware romepi_1.0.0.c
  • amd epyc_7542_firmware romepi_1.0.0.c
  • amd epyc_7532_firmware romepi_1.0.0.c
  • amd epyc_7502p_firmware romepi_1.0.0.c
  • amd epyc_7502_firmware romepi_1.0.0.c
  • amd epyc_7452_firmware romepi_1.0.0.c
  • amd epyc_7402_firmware romepi_1.0.0.c
  • amd epyc_7402p_firmware romepi_1.0.0.c
  • amd epyc_7352_firmware romepi_1.0.0.c
  • amd epyc_7302p_firmware romepi_1.0.0.c
  • amd epyc_7302_firmware romepi_1.0.0.c

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
19 mo ago

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 8% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.1 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
NVD 3.1 7.1 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
CNA 3.1 7.1 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

Affected products

  • AMD 2nd Gen EPYC
  • AMD 3rd Gen EPYC

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.