CVE-2025-20064 in Reference Platform
Summary
by MITRE • 03/11/2026
Improper input validation in the UEFI FlashUcAcmSmm module for some Intel(R) reference platforms may allow an escalation of privilege. System software adversary with a privileged user combined with a high complexity attack may enable local code execution. This result may potentially occur via local access when attack requirements are not present without special internal knowledge and requires no user interaction. The potential vulnerability may impact the confidentiality (high), integrity (high) and availability (high) of the vulnerable system, resulting in subsequent system confidentiality (high), integrity (high) and availability (high) impacts.
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Analysis
by VulDB Data Team • 05/01/2026
The vulnerability identified as CVE-2025-20064 resides within the UEFI FlashUcAcmSmm module of certain Intel reference platforms, representing a critical privilege escalation flaw that operates at the system firmware level. This issue stems from inadequate input validation mechanisms within the Secure Monitor Mode component, which is responsible for handling sensitive system operations during the boot process. The flaw exists in the communication channel between the system software and the SMM module, where insufficient sanitization of input parameters allows malicious code to manipulate the execution flow. The vulnerability is particularly concerning because it operates within the UEFI environment, which represents one of the most privileged execution contexts in modern computing platforms, making it a prime target for sophisticated adversaries seeking persistent system control. The security implications extend beyond simple privilege escalation to encompass complete system compromise, as this vulnerability operates at a level below the operating system kernel.
The technical exploitation of this vulnerability requires an adversary to possess elevated privileges within the system, combined with a high complexity attack vector that leverages the improper input validation within the FlashUcAcmSmm module. The attack scenario involves crafting malicious input that bypasses the validation checks implemented in the SMM module, ultimately leading to arbitrary code execution within the most privileged system context. This flaw manifests through the failure to properly validate data received from system software components, allowing attackers to inject malicious payloads that can manipulate firmware operations. The vulnerability's impact is amplified by the fact that it requires no user interaction, meaning that once an attacker gains access to a privileged account, they can immediately leverage this weakness without additional social engineering or complex exploitation techniques. The attack requires local access but does not demand user interaction, making it particularly dangerous in environments where privileged accounts are compromised or where attackers have already established a foothold within the system.
The operational impact of CVE-2025-20064 is severe across all three fundamental security principles, affecting confidentiality, integrity, and availability at a high level. The confidentiality impact is particularly high because successful exploitation could allow attackers to access sensitive system information, including cryptographic keys, system configuration data, and potentially user credentials stored within the firmware. The integrity impact is equally concerning as the vulnerability enables modification of critical system firmware components, potentially leading to persistent backdoors or complete system corruption. Availability is compromised through the potential for system crashes or complete system lockouts that could render the platform unusable. This vulnerability aligns with CWE-20, which describes "Improper Input Validation," and represents a classic case of insufficient validation of inputs to critical system components. The attack pattern follows the MITRE ATT&CK framework's T1068, "Exploitation for Privilege Escalation," and T1014, "Rootkit," as successful exploitation could establish persistent access to the system firmware layer. The vulnerability's classification as high impact across all security dimensions reflects its potential to enable complete system compromise, particularly when combined with other attack vectors or when exploited by adversaries with sufficient knowledge of the target platform's firmware structure.
Organizations should implement immediate mitigations including firmware updates from Intel, which are expected to address the input validation gaps in the FlashUcAcmSmm module. System administrators should also consider implementing additional access controls and monitoring for unusual SMM activity, as well as conducting thorough security assessments of their firmware environments. The vulnerability's nature suggests that traditional endpoint protection solutions may not be sufficient to detect exploitation attempts, requiring specialized firmware security tools and continuous monitoring of system firmware integrity. Given the high impact potential and the fact that this vulnerability operates at the firmware level, organizations should also review their overall security posture and consider implementing additional protective measures such as secure boot configurations, firmware lockdown mechanisms, and regular firmware integrity verification procedures. The security community should monitor for related vulnerabilities in similar firmware modules and consider the broader implications for Intel reference platform security, as this vulnerability could potentially indicate similar issues in other firmware components that handle privileged operations.