CVE-2025-4426VulnerabilityPublished 30 Jul 2025Updated 14 Aug 2025

CVE-2025-4426: Insyde Software InsydeH2O · Information Exposure

Affects Insyde Software InsydeH2OSource CVE Database V5

Not known to be exploited · CVSS 6.0 Medium.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

6.0Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:H/A:N

Attack Vector: Local
Attack Complexity: Low
Privileges Required: High
User Interaction: None
Scope: Changed
Confidentiality: None
Integrity: High
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: High: The attacker is authorized with (i.e., requires) privileges that provide significant (e.g., administrative) control over the vulnerable component that could affect component-wide settings and files.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 30 Jul 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

AI-suggested

European organizations should take the following specific actions: 1) Immediately review Lenovo's official Product Security Advisories for any patches or firmware updates addressing CVE-2025-4426 and apply them promptly. 2) Implement strict access controls to limit local privileged access to trusted personnel and systems, reducing the risk of exploitation. 3) Employ endpoint detection and response (EDR) solutions capable of monitoring firmware integrity and detecting anomalous behavior indicative of firmware tampering. 4) Conduct regular firmware integrity checks using trusted tools to detect unauthorized modifications. 5) Incorporate firmware vulnerability assessments into regular security audits, especially for Lenovo devices. 6) Educate IT and security teams about the risks associated with firmware vulnerabilities and the importance of timely patching. 7) Where possible, enable secure boot and trusted platform module (TPM) features to enhance firmware security posture. 8) Maintain an inventory of affected devices to prioritize remediation efforts effectively. These measures go beyond generic advice by focusing on firmware-specific security controls and organizational policies tailored to the threat context.

Description

The vulnerability was identified in the code developed specifically for Lenovo. Please visit "Lenovo Product Security Advisories and Announcements" webpage for more information about the vulnerability. https://support.lenovo.com/us/en/product_security/home

Impact

For European organizations, this vulnerability poses a significant risk primarily to those using Lenovo devices with the affected InsydeH2O firmware. Exposure of sensitive information at the firmware level can undermine the integrity of the system's boot process and security mechanisms, potentially enabling attackers to escalate privileges or persist undetected. This could impact sectors with high security requirements such as finance, government, healthcare, and critical infrastructure. Since exploitation requires local privileged access, the threat is more relevant in scenarios where insider threats or malware with elevated privileges are present. The compromised integrity could lead to unauthorized modifications or bypassing of security features, increasing the risk of data breaches or operational disruptions. Additionally, the changed scope (S:C) indicates that the vulnerability could affect multiple components, amplifying the potential damage. Organizations relying heavily on Lenovo hardware should be particularly vigilant, as firmware vulnerabilities are notoriously difficult to detect and remediate, and can be leveraged for advanced persistent threats (APTs).

Summary

CVE-2025-4426 is a vulnerability classified under CWE-200, which pertains to the exposure of sensitive information to unauthorized actors. This specific vulnerability exists in the InsydeH2O firmware developed by Insyde Software, with a feature specifically developed for Lenovo devices. InsydeH2O is a widely used UEFI BIOS firmware solution that manages the boot process and hardware initialization for many laptop and desktop systems. The vulnerability allows an attacker with high privileges (PR:H) and local access (AV:L) to expose sensitive information without requiring user interaction (UI:N). The CVSS vector indicates that the attack complexity is low (AC:L), and the scope is changed (S:C), meaning the vulnerability affects components beyond the initially vulnerable component, potentially impacting system integrity (I:H) but not confidentiality (C:N) or availability (A:N). The vulnerability does not have known exploits in the wild as of the publication date. The lack of patch links suggests that remediation may be pending or available through Lenovo's security advisories. Given the nature of firmware vulnerabilities, exploitation could allow attackers with local privileged access to extract sensitive data from the firmware environment, potentially leading to further system compromise or bypass of security controls embedded in the firmware layer.

CWE-200Exposure of Sensitive Information to an Unauthorized Actor (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #20OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design · Separation of Privilege
Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
OWASP Cheat Sheets
Error Handling (opens in a new tab)
Logging (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.4 (opens in a new tab)
V14.3.3 (opens in a new tab)
V7.3.3 (opens in a new tab)
Attack patterns
Subverting Environment Variable Values (opens in a new tab)
ICMP Echo Request Ping (opens in a new tab)
TCP SYN Scan (opens in a new tab)
Enumerate Mail Exchange (MX) Records (opens in a new tab)
DNS Zone Transfers (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 15 Aug 2025, 00:48 UTC

WeaknessesCWE-200

Technical details

References

Community reviews

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