CVE-2025-53738 in Word
Summary
by MITRE • 08/12/2025
Use after free in Microsoft Office Word allows an unauthorized attacker to execute code locally.
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Analysis
by VulDB Data Team • 08/19/2025
The vulnerability identified as CVE-2025-53738 represents a critical use-after-free flaw in Microsoft Office Word that enables remote code execution through local privilege escalation. This vulnerability resides within the document processing engine of Microsoft Word, specifically when handling malformed or crafted documents that trigger memory management errors during document parsing operations. The flaw manifests when the application attempts to access memory that has already been freed, creating a scenario where an attacker can manipulate the program flow and potentially execute arbitrary code with the privileges of the affected user. The vulnerability is classified under CWE-416 as a use-after-free condition, which is a well-known class of memory safety issues that has historically led to numerous exploitation vectors in Microsoft Office applications. According to the ATT&CK framework, this vulnerability maps to T1059.001 for command and scripting interpreter and T1547.001 for registry run keys, as successful exploitation typically requires persistence mechanisms and command execution capabilities.
The technical exploitation of CVE-2025-53738 occurs when a malicious document is opened in Microsoft Word, triggering a sequence where the application allocates memory for document elements and subsequently frees that memory without proper nullification. An attacker can craft a document that causes the application to reference this freed memory location, leading to a controlled overwrite of memory contents. This memory corruption allows the attacker to redirect program execution flow and inject malicious code into the Word process memory space. The vulnerability is particularly dangerous because it operates within the legitimate application context, making it difficult to detect through traditional security controls and network monitoring systems. The exploitation typically requires the user to open a specially crafted document, but once executed, the attacker can leverage the elevated privileges of the Word process to perform system-level operations.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with a persistent foothold within the victim environment. Successful exploitation can lead to complete system compromise, data exfiltration, and lateral movement within network environments. The vulnerability affects multiple versions of Microsoft Office Word across different operating systems, making it a widespread concern for enterprise environments. Organizations that rely heavily on Word documents for business operations face significant risk, as the attack vector can be delivered through email attachments, web downloads, or file sharing systems. The vulnerability's exploitation requires minimal user interaction beyond document opening, making it particularly effective for social engineering campaigns and targeted attacks against specific organizations.
Mitigation strategies for CVE-2025-53738 should prioritize immediate patch deployment from Microsoft as the primary defense mechanism, as the vendor has released security updates addressing the memory management flaw. Organizations should implement strict document handling policies, including email filtering and document validation procedures that prevent potentially malicious files from reaching end users. Network segmentation and privilege separation can limit the potential damage from successful exploitation attempts. Security teams should monitor for unusual Word process behavior and implement application control measures that restrict document processing to trusted sources only. Additionally, regular security awareness training should emphasize the dangers of opening unexpected document attachments and the importance of verifying document sources before opening them. The vulnerability's classification as a use-after-free issue underscores the importance of memory safety practices in software development and the need for comprehensive code review processes to identify similar flaws in other applications.