CVE-2023-31100

SPI flash modification via unauthorized SMI access

Published Nov 14, 2023 · Updated Jul 28, 2025

Improper access control in Phoenix SecureCore Technology 4 SPI SMM Driver allows local users to modify the platform SPI flash. The SMI handler exposes unauthorized flash access, but Phoenix has not published the exact missing authorization check or command-validation error. Low-privileged local access is required; successful use permits firmware modification, compromising platform integrity and availability.

CVSS severity8.4
High
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in Phoenix SecureCore Technology 4 SPI SMM Driver allows local users to modify the platform SPI flash. The SMI handler exposes unauthorized flash access, but Phoenix has not published the exact missing authorization check or command-validation error. Low-privileged local access is required; successful use permits firmware modification, compromising platform integrity and availability.

The record

CVE
CVE-2023-31100
Published
Nov 14, 2023
Updated
Jul 28, 2025
Vendor
Phoenix Technologies
Product
SecureCore Technology 4
Classifications
CWE-284, T1542.001
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 14, 2023CVE publishedPublication date reported by the CVE source.
  2. Jul 28, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.3.0.0 <4.3.0.203
  2. Affected versionversion=4.3.1.0 <4.3.1.163
  3. Affected versionversion=4.4.0.0 <4.4.0.217
  4. Affected versionversion=4.5.0.0 <4.5.0.138

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Phoenix Technologies · SecureCore Technology 4version=4.3.0.0 <4.3.0.203; version=4.3.1.0 <4.3.1.163; version=4.4.0.0 <4.4.0.217; version=4.5.0.0 <4.5.0.138

Published CVSS scores

8.4Phoenix TechnologiesCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H
7.1NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control
T1542.001Pre-OS Boot: System Firmware

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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