CVE-2021-26344

Severity: high (CVSS 8.2 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-08-13 · updated 2026-06-17
Weakness: CWE-787

Description

An out of bounds memory write when processing the AMD PSP1 Configuration Block (APCB) could allow an attacker with access the ability to modify the BIOS image, and the ability to sign the resulting image, to potentially modify the APCB block resulting in arbitrary code execution.

Affected products

AMD Epyc 7001 Firmware: all versions
AMD Epyc 7203 Firmware: before milanpi_1.0.0.5 — fixed in milanpi_1.0.0.5
AMD Epyc 7203P Firmware: before milanpi_1.0.0.5 — fixed in milanpi_1.0.0.5
AMD Epyc 7232P Firmware: before romepi_1.0.0.c — fixed in romepi_1.0.0.c
AMD Epyc 7251 Firmware: all versions
AMD Epyc 7252 Firmware: before romepi_1.0.0.c — fixed in romepi_1.0.0.c
AMD Epyc 7261 Firmware: all versions
AMD Epyc 7262 Firmware: before romepi_1.0.0.c — fixed in romepi_1.0.0.c
AMD Epyc 7272 Firmware: before romepi_1.0.0.c — fixed in romepi_1.0.0.c
AMD Epyc 7281 Firmware: all versions
AMD Epyc 7282 Firmware: before romepi_1.0.0.c — fixed in romepi_1.0.0.c
AMD Epyc 72F3 Firmware: before milanpi_1.0.0.5 — fixed in milanpi_1.0.0.5
AMD Epyc 7301 Firmware: all versions
AMD Epyc 7302 Firmware: before romepi_1.0.0.c — fixed in romepi_1.0.0.c
AMD Epyc 7302P Firmware: before romepi_1.0.0.c — fixed in romepi_1.0.0.c
AMD Epyc 7303 Firmware: before milanpi_1.0.0.5 — fixed in milanpi_1.0.0.5
AMD Epyc 7303P Firmware: before milanpi_1.0.0.5 — fixed in milanpi_1.0.0.5
AMD Epyc 7313 Firmware: before milanpi_1.0.0.5 — fixed in milanpi_1.0.0.5
AMD Epyc 7313P Firmware: before milanpi_1.0.0.5 — fixed in milanpi_1.0.0.5
AMD Epyc 7343 Firmware: before milanpi_1.0.0.5 — fixed in milanpi_1.0.0.5
AMD Epyc 7351 Firmware: all versions
AMD Epyc 7351P Firmware: all versions
AMD Epyc 7352 Firmware: before romepi_1.0.0.c — fixed in romepi_1.0.0.c
AMD Epyc 7371 Firmware: all versions
AMD Epyc 7373X Firmware: before milanpi_1.0.0.5 — fixed in milanpi_1.0.0.5
AMD Epyc 73F3 Firmware: before milanpi_1.0.0.5 — fixed in milanpi_1.0.0.5
AMD Epyc 7401 Firmware: all versions
AMD Epyc 7401P Firmware: all versions
AMD Epyc 7402 Firmware: before romepi_1.0.0.c — fixed in romepi_1.0.0.c
AMD Epyc 7402P Firmware: before romepi_1.0.0.c — fixed in romepi_1.0.0.c

How to fix

Upgrade to a fixed version: AMD Epyc 7203 Firmware milanpi_1.0.0.5; AMD Epyc 7203P Firmware milanpi_1.0.0.5; AMD Epyc 7232P Firmware romepi_1.0.0.c; AMD Epyc 7252 Firmware romepi_1.0.0.c; AMD Epyc 7262 Firmware romepi_1.0.0.c; AMD Epyc 7272 Firmware romepi_1.0.0.c; AMD Epyc 7282 Firmware romepi_1.0.0.c; AMD Epyc 72F3 Firmware milanpi_1.0.0.5; AMD Epyc 7302 Firmware romepi_1.0.0.c; AMD Epyc 7302P Firmware romepi_1.0.0.c; AMD Epyc 7303 Firmware milanpi_1.0.0.5; AMD Epyc 7303P Firmware milanpi_1.0.0.5. Check the vendor advisory for mitigations.

References

https://www.amd.com/en/resources/product-security/bulletin/amd-sb-3003.html

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