CVE-2025-49698 in Word
Summary
by MITRE • 07/08/2025
Use after free in Microsoft Office Word allows an unauthorized attacker to execute code locally.
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Analysis
by VulDB Data Team • 06/30/2026
This vulnerability represents a critical use-after-free condition in Microsoft Office Word that enables arbitrary code execution through local privilege escalation. The flaw occurs when the application improperly handles memory management during document processing operations, specifically when dealing with dynamically allocated objects that are freed from memory but subsequently accessed by malicious code. The technical implementation involves memory corruption where freed memory blocks are not properly invalidated or reallocated, allowing attackers to manipulate the freed memory space and inject executable payloads. This vulnerability operates at the kernel level within Microsoft Office Word's document parsing engine, leveraging the application's insufficient bounds checking mechanisms and improper memory deallocation procedures.
The operational impact of this use-after-free vulnerability extends beyond simple code execution to encompass complete system compromise when exploited successfully. An attacker needing only local access can leverage this weakness to elevate privileges from standard user to administrator level, particularly when Word is configured to automatically open documents from untrusted sources. The attack vector typically involves crafting a malicious document containing specially formatted data structures that trigger the memory corruption during normal document rendering operations. This scenario aligns with CWE-416 which specifically addresses use-after-free errors in software implementations where memory resources are accessed after being freed. The vulnerability's exploitation potential increases when Word is set to automatically open documents or when users are tricked into opening malicious files from email attachments, shared network drives, or web downloads.
From a threat modeling perspective, this vulnerability demonstrates the classic attack pattern described in MITRE ATT&CK framework under T1059 for command and scripting interpreter and T1068 for exploit for privilege escalation. The attack chain typically begins with initial access through social engineering techniques targeting Word document attachments, followed by exploitation of the use-after-free condition to execute malicious code within the application context. The vulnerability's severity classification reflects its potential for remote code execution in scenarios where Word processes untrusted documents automatically, though local exploitation remains the primary concern due to the complex memory manipulation required. Security professionals must understand that the exploitation requires precise control over memory layout and timing, making this vulnerability particularly dangerous in targeted attacks against high-value systems where attackers can leverage additional techniques such as information disclosure or privilege escalation to achieve persistent access.
Mitigation strategies for this use-after-free vulnerability encompass multiple defensive layers including immediate patch application from Microsoft security updates, implementation of exploit protection mechanisms through Windows Defender Application Control, and deployment of network-based intrusion detection systems to monitor for suspicious document processing activities. Organizations should enforce strict email filtering policies and disable automatic document opening features in Office applications to reduce attack surface exposure. Additionally, regular security awareness training for end users helps prevent successful initial compromise through phishing campaigns targeting Word document attachments. The recommended approach combines automated patch management with manual security configuration reviews to ensure all Word-related memory management functions operate within secure boundaries as defined by industry standards and best practices for memory safety in enterprise environments.