CVE-2025-20073: Intel UEFI DXE Information Disclosure Flaw

CVE-2025-20073 Overview

CVE-2025-20073 is a BIOS/UEFI vulnerability affecting Intel Reference Platforms caused by improper buffer restrictions in the UEFI DXE (Driver Execution Environment) module. This vulnerability may allow an attacker with privileged local access to potentially expose sensitive data through information disclosure.

Critical Impact

Privileged local attackers may leverage improper buffer restrictions in the UEFI DXE module to gain unauthorized access to sensitive system information, potentially compromising system confidentiality.

Affected Products

• Intel Reference Platforms with vulnerable UEFI firmware
• Systems utilizing affected UEFI DXE modules

Discovery Timeline

• 2026-03-10 - CVE-2025-20073 published to NVD
• 2026-03-11 - Last updated in NVD database

Technical Details for CVE-2025-20073

Vulnerability Analysis

This vulnerability stems from improper buffer restrictions (CWE-119) within the UEFI DXE module on Intel Reference Platforms. The DXE phase is a critical stage in the UEFI boot process where most firmware drivers and protocols are initialized. During this phase, improper handling of buffer boundaries can lead to unintended information exposure.

The attack requires local access to the system and elevated privileges. While the complexity of exploitation is high, no user interaction is required once an attacker has the necessary access level. The impact is limited to confidentiality with low severity, meaning that while some data exposure is possible, it does not affect system integrity or availability.

Root Cause

The root cause of CVE-2025-20073 is improper buffer restrictions (CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer) in the UEFI DXE module. This class of vulnerability occurs when software performs operations on a memory buffer without properly validating the boundaries, potentially allowing read operations beyond the intended buffer limits.

In the context of UEFI firmware, DXE modules handle critical system initialization tasks, and buffer handling errors in these components can expose sensitive data stored in memory regions that should not be accessible.

Attack Vector

The vulnerability requires local access to the target system combined with high-level privileges. An attacker would need to:

1. Gain privileged access to the target system (administrative or root-level access)
2. Interact with the UEFI DXE module through legitimate system interfaces
3. Craft specific inputs that trigger the improper buffer restriction condition
4. Read data that has been exposed due to the buffer handling error

Due to the high attack complexity and privileged access requirements, exploitation is not trivial and requires significant technical expertise and system access.

The vulnerability manifests in the UEFI DXE module's buffer handling operations. For detailed technical information, refer to the Intel Security Advisory SA-01234.

Detection Methods for CVE-2025-20073

Indicators of Compromise

• Unexpected UEFI firmware modification or tampering attempts
• Anomalous system boot behavior or extended DXE phase execution
• Unauthorized access attempts to firmware interfaces from privileged accounts

Detection Strategies

• Monitor for unusual privileged user activity targeting UEFI/BIOS interfaces
• Implement firmware integrity monitoring to detect unauthorized modifications
• Enable secure boot and UEFI secure boot logging where available
• Review system logs for suspicious firmware-related events

Monitoring Recommendations

• Deploy endpoint detection and response (EDR) solutions capable of monitoring firmware-level activity
• Implement privileged access management (PAM) to track and audit all elevated access
• Regularly audit user accounts with administrative privileges for unauthorized access patterns

How to Mitigate CVE-2025-20073

Immediate Actions Required

• Review the Intel Security Advisory SA-01234 for affected product versions and patch availability
• Restrict privileged access to affected systems to authorized personnel only
• Audit current UEFI firmware versions across Intel Reference Platform deployments
• Implement network segmentation to limit access to systems with vulnerable firmware

Patch Information

Intel has released a security advisory addressing this vulnerability. Organizations should consult the Intel Security Advisory SA-01234 for specific patch information, affected firmware versions, and updated firmware download links. Apply the recommended firmware updates following Intel's guidance and your organization's change management procedures.

Workarounds

• Limit privileged access to affected systems until patches can be applied
• Enable UEFI Secure Boot to add an additional layer of firmware integrity protection
• Implement strict access controls on BIOS/UEFI configuration interfaces
• Consider physical security measures to prevent unauthorized local access to affected systems

# Verify current UEFI Secure Boot status (Linux)
mokutil --sb-state

# Check UEFI firmware information
dmidecode -t bios