CVE-2025-27729 in Windows
Summary
by MITRE • 04/08/2025
Use after free in Windows Shell allows an unauthorized attacker to execute code locally.
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Analysis
by VulDB Data Team • 05/11/2026
This vulnerability represents a critical use-after-free condition in the Windows Shell component that enables local privilege escalation through unauthorized code execution. The flaw occurs when the shell process improperly handles memory allocation and deallocation, creating a scenario where freed memory blocks can be accessed and overwritten by malicious code. Such vulnerabilities typically arise from inadequate memory management practices where objects are not properly validated before access, allowing attackers to manipulate the execution flow of legitimate processes.
The technical implementation of this vulnerability leverages the Windows Shell's handling of file operations and object references within the graphical user interface environment. When a malicious user triggers specific shell operations, the system allocates memory for shell objects, performs operations on them, and subsequently frees the memory. However, the improper handling allows for a race condition or memory corruption scenario where attacker-controlled data can be placed in the freed memory space and later executed when the shell attempts to access the reclaimed memory region. This pattern aligns with common software security weaknesses classified under CWE-416, which specifically addresses use-after-free vulnerabilities in memory management.
The operational impact of this vulnerability extends beyond simple code execution as it provides a pathway for attackers to escalate privileges within the Windows environment. Local attackers can exploit this weakness to execute arbitrary code with the privileges of the target user, potentially leading to full system compromise if the victim has administrative rights. The attack vector typically involves crafting malicious files or shell operations that trigger the vulnerable code path, making this particularly dangerous in environments where users may encounter untrusted content through legitimate shell interactions. This vulnerability directly relates to ATT&CK technique T1068, which covers local privilege escalation through the exploitation of system vulnerabilities.
Mitigation strategies for this use-after-free vulnerability require immediate patching of the Windows Shell components through official security updates from Microsoft. System administrators should implement comprehensive monitoring for suspicious shell activity and memory access patterns that may indicate exploitation attempts. Additional protective measures include implementing application whitelisting policies to restrict execution of unauthorized binaries, enabling exploit protection features such as Data Execution Prevention, and maintaining regular security audits of shell-related configurations. The vulnerability underscores the importance of proper memory management practices in system-level components and highlights the necessity of rigorous code review processes for critical Windows subsystems to prevent similar issues from occurring in future releases.