CVE-2023-35841Public exploit

Local privilege escalation via exposed firmware IOCTLs

Published May 14, 2024 · Updated Jul 28, 2025

Privilege escalation in Phoenix WinFlash Driver before 4.5.0.0 allows local users to modify system firmware through exposed IOCTLs. TdkLib64.sys accepts encoded IOCTL request buffers from non-admin callers and exposes arbitrary port I/O and memory-mapped I/O used to reach SPI flash. A local low-privileged application can erase or alter firmware and obtain elevated privileges; firmware erasure can leave the system unbootable.

CVSS severity7.8
High
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Privilege escalation in Phoenix WinFlash Driver before 4.5.0.0 allows local users to modify system firmware through exposed IOCTLs. TdkLib64.sys accepts encoded IOCTL request buffers from non-admin callers and exposes arbitrary port I/O and memory-mapped I/O used to reach SPI flash. A local low-privileged application can erase or alter firmware and obtain elevated privileges; firmware erasure can leave the system unbootable.

The record

CVE
CVE-2023-35841
Published
May 14, 2024
Updated
Jul 28, 2025
Vendor
Phoenix Technologies
Product
WinFlash Driver
Classifications
CWE-732, CWE-782, CAPEC-233, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 14, 2024CVE 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=0 <4.5.0
  2. Affected versionversion=0 <4.5.0.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Phoenix Technologies · WinFlash Driverversion=0 <4.5.0; version=0 <4.5.0.0

Published CVSS scores

7.8Phoenix TechnologiesCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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 exploitPublished

Weakness, pattern, technique

CWE-732Incorrect Permission Assignment for Critical Resource
CWE-782Exposed IOCTL with Insufficient Access Control
CAPEC-233Privilege Escalation
T1068Exploitation for Privilege Escalation

Public exploit references

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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