Microsoft has recently addressed two significant security vulnerabilities within its Windows BitLocker encryption feature, identified as CVE-2025-54911 and CVE-2025-54912. Disclosed on September 9, 2025, these flaws have been assigned an Important severity rating due to their potential to allow authorized attackers to escalate privileges to SYSTEM level on affected machines.
Understanding the Vulnerabilities
Both CVE-2025-54911 and CVE-2025-54912 are classified as Use-After-Free vulnerabilities, a type of memory corruption issue cataloged under CWE-416. This occurs when a program continues to use a pointer to a memory location after it has been freed or deallocated. If an attacker can influence the data written to this deallocated space, they can manipulate the program’s execution flow, potentially leading to arbitrary code execution.
In the context of BitLocker, these vulnerabilities could be exploited by an attacker with low-level privileges on the target system. By leveraging these flaws, the attacker could execute code with SYSTEM-level privileges, the highest level of access on a Windows system. This would grant them the ability to install programs, view, change, or delete data, and create new accounts with full user rights.
Exploitation Conditions
According to Microsoft’s Common Vulnerability Scoring System (CVSS) metrics, exploiting these vulnerabilities requires the attacker to have existing low-level privileges on the target system. Additionally, some form of user interaction is necessary for the exploit to succeed. This means that an attacker would need to trick an authorized user into performing a specific action, such as opening a malicious file or clicking on a deceptive link. While these prerequisites make remote, automated attacks more challenging, they do not eliminate the risk, especially in scenarios where an attacker has already gained an initial foothold on the system.
Mitigation Measures
In response to these discoveries, Microsoft has released patches as part of the September 2025 Patch Tuesday update. Users and administrators are strongly advised to apply these updates promptly to protect their systems from potential exploitation. While Microsoft has assessed the likelihood of exploitation as less likely, the severity of the potential impact necessitates immediate action.
The discovery of CVE-2025-54912 was credited to Hussein Alrubaye, working with Microsoft, highlighting the importance of collaboration between the company and external security researchers in identifying and resolving critical security issues.
Broader Implications
The presence of two distinct Use-After-Free vulnerabilities in a critical security component like BitLocker underscores the ongoing challenges in maintaining memory safety in complex software. It also highlights the importance of regular security assessments and prompt patch management to mitigate potential risks.
Users are advised to check for updates through the standard Windows Update service to ensure their systems are no longer susceptible to these privilege escalation flaws.
