CVE-2025-47953: Microsoft 365 Apps Use After Free Flaw

CVE-2025-47953 Overview

CVE-2025-47953 is a use after free vulnerability affecting Microsoft Office products that allows an unauthorized attacker to execute arbitrary code locally. This memory corruption flaw occurs when the application continues to use memory after it has been freed, creating an opportunity for attackers to manipulate program execution flow and potentially gain control of the affected system.

Critical Impact

Successful exploitation enables unauthorized local code execution with the potential for complete system compromise, including confidentiality, integrity, and availability impacts.

Affected Products

• Microsoft 365 Apps for Enterprise
• Microsoft Office (2016, 2019, and Android versions)
• Microsoft Office Long Term Servicing Channel (2021 and 2024)

Discovery Timeline

• June 10, 2025 - CVE-2025-47953 published to NVD
• July 9, 2025 - Last updated in NVD database

Technical Details for CVE-2025-47953

Vulnerability Analysis

This use after free vulnerability (CWE-641) exists within Microsoft Office's memory handling routines. Use after free conditions occur when a program continues to reference memory after it has been deallocated, leading to undefined behavior. In this case, the vulnerability allows an attacker with local access to execute code without requiring any user interaction or special privileges.

The vulnerability affects the core Office application suite across multiple platforms and deployment channels, including the Android mobile version. When exploited, the flaw can lead to arbitrary code execution with the permissions of the current user, potentially compromising sensitive documents and system resources.

Root Cause

The root cause stems from improper memory management within Microsoft Office where freed memory pointers are not properly invalidated. When the application attempts to access this freed memory, an attacker can potentially control the data that occupies that memory region, enabling arbitrary code execution. This type of vulnerability typically occurs due to complex object lifecycle management in large codebases.

Attack Vector

The attack vector is local, meaning an attacker needs to have some level of access to the target system to exploit this vulnerability. The attack complexity is low, and no user interaction is required for exploitation. An attacker could craft a malicious document or leverage local access to trigger the vulnerable code path, causing the use after free condition to execute attacker-controlled code.

The vulnerability mechanism involves triggering the allocation and deallocation of memory objects in a specific sequence that leaves dangling pointers. When these pointers are subsequently dereferenced, the attacker can redirect execution to malicious code. For detailed technical information, refer to the Microsoft Security Update for CVE-2025-47953.

Detection Methods for CVE-2025-47953

Indicators of Compromise

• Unusual process behavior from Office applications such as WINWORD.EXE, EXCEL.EXE, or POWERPNT.EXE spawning unexpected child processes
• Memory access violations or application crashes in Office components that may indicate exploitation attempts
• Suspicious document files with anomalous structures or embedded objects designed to trigger memory corruption
• Unexpected code execution originating from Office process memory space

Detection Strategies

• Deploy endpoint detection and response (EDR) solutions configured to monitor for memory corruption exploitation patterns in Office processes
• Implement application behavior monitoring to detect anomalous Office application activities such as unusual API calls or memory access patterns
• Use security tools capable of detecting use after free exploitation techniques, including heap spray and memory manipulation indicators
• Monitor for Office processes exhibiting abnormal execution flow or loading unexpected modules

Monitoring Recommendations

• Enable enhanced logging for Office application events and correlate with endpoint telemetry
• Configure alerts for Office processes attempting to execute code from heap or stack memory regions
• Implement file integrity monitoring on Office installation directories to detect tampering
• Review system logs for repeated Office application crashes that may indicate exploitation attempts

How to Mitigate CVE-2025-47953

Immediate Actions Required

• Apply the latest Microsoft security updates for all affected Office products immediately
• Ensure all Microsoft 365 Apps and Office installations are configured for automatic updates
• Restrict local access to systems running vulnerable Office versions until patches are applied
• Review and audit documents from untrusted sources before opening in affected Office applications

Patch Information

Microsoft has released security updates to address this vulnerability. Administrators should apply patches through Windows Update, Microsoft Update, or the Microsoft Update Catalog. For detailed patch information and download links, visit the Microsoft Security Update for CVE-2025-47953.

Organizations using Microsoft 365 Apps for Enterprise should ensure their update channel is configured to receive the latest security updates. LTSC users should apply the appropriate cumulative updates for their Office version (2021 or 2024).

Workarounds

• Implement application whitelisting to restrict code execution from Office process memory
• Enable exploit protection features such as Windows Defender Exploit Guard with appropriate mitigations for Office applications
• Consider running Office applications in isolated environments or sandboxes for processing untrusted documents
• Limit local access to systems with vulnerable Office installations to essential personnel only

# Enable Windows Defender Exploit Guard for Office applications
# Run in PowerShell as Administrator
Set-ProcessMitigation -Name WINWORD.EXE -Enable DEP,BottomUp,SEHOP
Set-ProcessMitigation -Name EXCEL.EXE -Enable DEP,BottomUp,SEHOP
Set-ProcessMitigation -Name POWERPNT.EXE -Enable DEP,BottomUp,SEHOP