CVE-2025-4425: Lenovo Buffer Overflow Vulnerability

CVE-2025-4425 Overview

CVE-2025-4425 is a stack-based buffer overflow [CWE-121] affecting code developed specifically for Lenovo systems. The flaw resides in firmware components documented in Insyde Security Advisory SA-2025007 and referenced through the Lenovo Product Security Portal.

Exploitation requires local access and high privileges but yields high impact to confidentiality, integrity, and availability. The scope is marked as changed, indicating the vulnerability can affect components beyond the initially compromised security authority, consistent with firmware-level code execution.

Critical Impact
A local attacker holding elevated privileges can trigger a stack overflow in Lenovo-specific firmware code to execute arbitrary code below the operating system boundary, undermining OS-level security controls.

Affected Products

Lenovo systems shipping the affected Lenovo-specific firmware code
Insyde H2O UEFI firmware components referenced in advisory SA-2025007
Specific models and firmware versions are enumerated on the Lenovo Product Security Portal

Discovery Timeline

2025-07-30 - CVE-2025-4425 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-4425

Vulnerability Analysis

The vulnerability is a stack-based buffer overflow classified under [CWE-121]. The affected code copies attacker-influenced input into a fixed-size stack buffer without validating the input length against the destination size. When the input exceeds the buffer boundary, adjacent stack memory including saved return addresses and frame pointers is overwritten.

Because the vulnerable code executes in a privileged firmware or Lenovo-specific pre-boot context, successful exploitation can hijack execution flow before operating system protections take effect. The changed scope value in the CVSS vector reflects that a compromise crosses the trust boundary of the vulnerable component.

The attack requires local access and high privileges, meaning an attacker must already control an elevated account on the target system. No user interaction is required once the attacker can invoke the vulnerable code path. Exploitation of this class of firmware flaw typically enables persistence that survives operating system reinstallation.

Root Cause

The root cause is missing or incorrect bounds checking when writing data into a stack-allocated buffer inside code developed for Lenovo. Unsafe copy operations, such as unchecked string or memory copy routines, allow attacker-controlled length or content to exceed the buffer capacity and corrupt the stack frame.

Attack Vector

A local attacker with administrative privileges submits a crafted input to the vulnerable firmware interface. The oversized input overflows the stack buffer, overwrites the saved return address, and redirects execution to attacker-supplied code. See the Insyde Security Advisory SA-2025007 for the affected interface and remediated versions.

Detection Methods for CVE-2025-4425

Indicators of Compromise

Unexpected firmware version strings or checksum mismatches reported by platform attestation and fwupd-style inventory tools
Unauthorized SMM or UEFI runtime driver modifications detected by measured boot logs and TPM PCR value drift
Local privileged processes issuing unusual SMI or firmware variable write sequences prior to reboot

Detection Strategies

Compare installed firmware versions against the fixed versions listed in the Lenovo advisory and flag hosts below the patched baseline
Monitor kernel and driver telemetry for privileged processes invoking firmware update or configuration interfaces outside sanctioned maintenance windows
Correlate crash telemetry showing stack corruption or unexpected resets during pre-boot or firmware service calls

Monitoring Recommendations

Enable and centrally collect UEFI measured boot logs and validate TPM PCR values against a known-good baseline
Track administrative access events on endpoints, since exploitation requires prior high-privilege access
Ingest platform firmware inventory into a SIEM or asset management system to sustain patch-state visibility across the fleet

How to Mitigate CVE-2025-4425

Immediate Actions Required

Identify affected Lenovo systems using vendor inventory tools and cross-reference against the model list on the Lenovo Product Security Portal
Apply the firmware update supplied by Lenovo as soon as it is available for the affected platforms
Restrict local administrative access, since exploitation requires high privileges on the target host
Enforce Secure Boot and enable measured boot with TPM attestation to detect unauthorized firmware modifications

Patch Information

Refer to the Lenovo Product Security Advisories and Announcements page for the list of affected models and fixed firmware versions. Upstream fixes are described in Insyde Security Advisory SA-2025007. Deploy updates through Lenovo System Update, fwupd on Linux, or enterprise firmware management tooling.

Workarounds

Limit accounts with local administrative privileges to reduce the population of users capable of reaching the vulnerable code path
Require multi-factor authentication for privileged local logons and monitor administrative activity closely
Enable BIOS or UEFI setup passwords and disable unused firmware update mechanisms until patches are applied

bash

# Example: query firmware version on Linux to compare against fixed baseline
sudo dmidecode -s bios-version
sudo dmidecode -s bios-release-date
sudo fwupdmgr get-devices
sudo fwupdmgr refresh && sudo fwupdmgr update