CVE-2025-4424

Protected-variable overwrite via unsanitized SMM arguments

Published Jul 30, 2025 · Updated Aug 14, 2025

Improper input validation in InsydeH2O before L05.05.40.011803.172079 allows local users to overwrite locked UEFI variables. The SetupAutomationSmm Callback04 handler passes attacker-controlled variable names, GUIDs, sizes, and data to SmmSetVariable without filtering. High local privileges are required; successful exploitation changes protected firmware state and can bypass UEFI security mechanisms, with no reported disclosure or service interruption.

CVSS severity6.0
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in InsydeH2O before L05.05.40.011803.172079 allows local users to overwrite locked UEFI variables. The SetupAutomationSmm Callback04 handler passes attacker-controlled variable names, GUIDs, sizes, and data to SmmSetVariable without filtering. High local privileges are required; successful exploitation changes protected firmware state and can bypass UEFI security mechanisms, with no reported disclosure or service interruption.

The record

CVE
CVE-2025-4424
Published
Jul 30, 2025
Updated
Aug 14, 2025
Vendor
Insyde Software
Product
InsydeH2O UEFI BIOS
Classifications
CWE-20, T1542.001
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Jul 30, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 14, 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=Feature developed for Lenovo <L05.05.40.011803.172079

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Insyde Software · InsydeH2O UEFI BIOSversion=Feature developed for Lenovo <L05.05.40.011803.172079

Published CVSS scores

6.0Insyde SoftwareCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:H/A:N

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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
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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