CVE-2023-31355

MEDIUM

AMD EPYC 7003 Series Firmware < milanpi_1.0.0.d - Memory Read via UMC Seed Overwrite

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2023-31355. PoCs published by Freax13.

AI-analyzed exploit summary This PoC exploits a vulnerability in AMD SEV firmware (CVE-2023-31355) by corrupting the UMC key seed to decrypt arbitrary memory of an SEV-SNP guest after decommissioning. The exploit leverages uninitialized RMP entries to overwrite the key seed at address 0.

Description

Improper restriction of write operations in SNP firmware could allow a malicious hypervisor to overwrite a guest's UMC seed potentially allowing reading of memory from a decommissioned guest.

Exploits (1)

nomisec WORKING POC 8 stars
by Freax13 · poc
https://github.com/Freax13/cve-2023-31355-poc

This PoC exploits a vulnerability in AMD SEV firmware (CVE-2023-31355) by corrupting the UMC key seed to decrypt arbitrary memory of an SEV-SNP guest after decommissioning. The exploit leverages uninitialized RMP entries to overwrite the key seed at address 0.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Complex
Reliability
Reliable
Target: AMD SEV firmware version 1.55.16
No auth needed
Prerequisites: Modified BIOS settings (RMP covered area set to 64GiB) · Patched Linux kernel (snp-host-v10 branch) · Victim SEV-SNP guest running
devstral-2 · analyzed Feb 16, 2026 Full analysis →

References (1)

Core 1

Scores

CVSS v3 6.0
EPSS 0.0044
EPSS Percentile 35.4%
Attack Vector LOCAL
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-119 CWE-787
Status published
Products (50)
amd/epyc_7203_firmware < milanpi_1.0.0.d
amd/epyc_7203p_firmware < milanpi_1.0.0.d
amd/epyc_72f3_firmware < milanpi_1.0.0.d
amd/epyc_7303_firmware < milanpi_1.0.0.d
amd/epyc_7303p_firmware < milanpi_1.0.0.d
amd/epyc_7313_firmware < milanpi_1.0.0.d
amd/epyc_7313p_firmware < milanpi_1.0.0.d
amd/epyc_7343_firmware < milanpi_1.0.0.d
amd/epyc_7373x_firmware < milanpi_1.0.0.d
amd/epyc_73f3_firmware < milanpi_1.0.0.d
... and 40 more
Published Aug 05, 2024
Tracked Since Feb 18, 2026