KB5002848 is a March 10, 2026 security update for Microsoft Word 2016 that resolves critical vulnerabilities including remote code execution and information disclosure flaws. This update applies to both 32-bit and 64-bit editions of Office 2016 and requires approximately 45 MB of disk space.
KB5002848Microsoft OfficeMicrosoft Office
KB5002848 — Security Update for Microsoft Word 2016
KB5002848 is a security update released March 10, 2026, that addresses multiple vulnerabilities in Microsoft Word 2016, including remote code execution and information disclosure flaws affecting both 32-bit and 64-bit editions.
Emanuel DE ALMEIDAKB5002848 is a security update released March 10, 2026, that addresses multiple vulnerabilities in Microsoft Word 2016, including remote code execution and information disclosure flaws affecting both 32-bit and 64-bit editions.
Overview
In This Article
- Issue Description
- Root Cause
- 1Fixes remote code execution vulnerability in document parsing engine
- 2Resolves information disclosure vulnerability in memory handling
- 3Strengthens macro security enforcement mechanisms
- 4Improves document format compatibility and stability
- Installation
- Known Issues
- Frequently Asked Questions
Applies to
Microsoft Office 2016 (32-bit edition)Microsoft Office 2016 (64-bit edition)Microsoft Word 2016 standalone
Issue Description
Issue Description
This security update addresses several vulnerabilities in Microsoft Word 2016 that could allow attackers to execute arbitrary code or access sensitive information:
- Remote Code Execution: Specially crafted Word documents could trigger memory corruption vulnerabilities, allowing attackers to execute code with the same privileges as the current user
- Information Disclosure: Malformed documents could cause Word to disclose contents of memory, potentially exposing sensitive data
- Document Parsing Errors: Certain document formats could cause Word to crash or behave unexpectedly when opened
- Macro Security Bypass: Under specific conditions, macro security settings could be circumvented, allowing unauthorized macro execution
These vulnerabilities primarily affect users who open Word documents from untrusted sources, including email attachments and downloaded files.
Root Cause
Root Cause
The vulnerabilities stem from improper validation of user input in Word's document parsing engine and insufficient bounds checking in memory allocation routines. The remote code execution flaw occurs when Word processes specially crafted document elements without properly validating their size and structure, leading to buffer overflows. The information disclosure vulnerability results from inadequate memory initialization when handling certain document properties.
1
Fixes remote code execution vulnerability in document parsing engine
This update patches the Word document parsing engine to properly validate document structure and element sizes before processing. The fix implements enhanced bounds checking for document elements and improves memory allocation validation to prevent buffer overflows. Specifically addresses vulnerabilities in RTF, DOCX, and legacy DOC format parsing that could be exploited through maliciously crafted documents.
Components Updated:
winword.exe- Core Word application binarywwlib.dll- Word library containing document parsing routinesmsword.olb- Word object library
2
Resolves information disclosure vulnerability in memory handling
Addresses improper memory initialization that could lead to disclosure of sensitive information when processing certain document properties. The update ensures that memory buffers are properly cleared before use and implements additional validation for document metadata processing.
Security Improvements:
- Enhanced memory initialization routines
- Improved validation of document properties and metadata
- Strengthened access controls for memory allocation
3
Strengthens macro security enforcement mechanisms
Updates macro security validation to prevent bypass scenarios where macro execution could occur despite security settings. The fix ensures that macro security policies are consistently enforced across all document types and loading scenarios.
Macro Security Enhancements:
- Improved macro signature validation
- Enhanced trusted location verification
- Strengthened macro execution policy enforcement
4
Improves document format compatibility and stability
Resolves parsing issues with certain document formats that could cause application crashes or unexpected behavior. Updates include improved error handling for malformed documents and enhanced compatibility with legacy document formats.
Stability Improvements:
- Better error handling for corrupted documents
- Enhanced compatibility with legacy DOC formats
- Improved recovery mechanisms for parsing errors
Installation
Installation
KB5002848 is available through multiple distribution channels:
Microsoft Update: The update is automatically delivered to systems with automatic updates enabled. Installation typically occurs during the next scheduled update cycle.
Microsoft Update Catalog: Manual download available from the Microsoft Update Catalog for enterprise deployment scenarios. The update package is approximately 45 MB for both 32-bit and 64-bit versions.
Office Click-to-Run: For Click-to-Run installations of Office 2016, the update is delivered through the Office update channel and can be installed via File > Account > Update Options > Update Now.
System Requirements:
- Microsoft Office 2016 (any edition)
- 45 MB available disk space
- Administrative privileges for installation
- No prerequisite updates required
Installation Process:
- Close all Office applications before installation
- Run the update package with administrative privileges
- Restart may be required depending on system configuration
- Verify installation using
Programs and Featuresor Office update history
Note: Enterprise administrators can deploy this update through Windows Server Update Services (WSUS), Microsoft System Center Configuration Manager (SCCM), or Microsoft Intune.
Known Issues
Known Issues
The following issues have been reported after installing KB5002848:
Document Compatibility: Some users may experience formatting changes in documents created with very old versions of Word (Word 97 and earlier). This primarily affects documents with complex formatting or embedded objects.
Add-in Compatibility: Third-party Word add-ins that rely on undocumented APIs may experience compatibility issues. Contact add-in vendors for updated versions compatible with this security update.
Performance Impact: Users may notice slightly longer document opening times due to enhanced security validation. This is expected behavior and indicates the security improvements are functioning correctly.
Macro Execution: Some previously functional macros may require re-signing or trust configuration due to strengthened security enforcement.
Important: If you experience issues after installing this update, you can uninstall it through Programs and Features > View installed updates. However, this will leave your system vulnerable to the security issues addressed by this update.
Workarounds:
- For document compatibility issues, save affected documents in newer formats (DOCX)
- For add-in issues, check with vendors for updated versions or disable problematic add-ins temporarily
- For macro issues, review macro security settings and re-sign macros if necessary
Overview
KB5002848 is a critical security update for Microsoft Word 2016 released on March 10, 2026. This update addresses multiple security vulnerabilities that could allow remote code execution and information disclosure attacks. The update applies to all editions of Microsoft Office 2016, including both 32-bit and 64-bit versions, as well as standalone Word 2016 installations.
Security Vulnerabilities Addressed
This update resolves several critical security flaws in Word 2016's document processing engine:
Remote Code Execution Vulnerabilities
The most severe vulnerabilities addressed by this update involve remote code execution flaws in Word's document parsing engine. These vulnerabilities could be exploited by attackers who convince users to open specially crafted Word documents. Successful exploitation could allow attackers to execute arbitrary code with the same privileges as the current user.
The vulnerabilities affect multiple document formats:
- DOCX Format: Improper validation of XML elements in DOCX files could lead to memory corruption
- RTF Format: Buffer overflow conditions in RTF parsing routines
- Legacy DOC Format: Integer overflow vulnerabilities in binary document structure parsing
Information Disclosure Vulnerabilities
The update also addresses information disclosure vulnerabilities that could allow attackers to access sensitive information from system memory. These flaws occur when Word processes certain document properties without properly initializing memory buffers, potentially exposing data from previous operations.
Macro Security Bypass
A vulnerability in macro security enforcement could allow attackers to bypass macro execution restrictions under specific conditions. This could enable unauthorized macro execution even when macro security is configured to block untrusted macros.
Affected Systems
This security update applies to the following Microsoft Office products:
| Product | Version | Architecture | Update Required |
|---|---|---|---|
| Microsoft Office 2016 | 16.0.x | 32-bit | Yes |
| Microsoft Office 2016 | 16.0.x | 64-bit | Yes |
| Microsoft Word 2016 (Standalone) | 16.0.x | 32-bit | Yes |
| Microsoft Word 2016 (Standalone) | 16.0.x | 64-bit | Yes |
The update is compatible with all supported Windows operating systems that can run Office 2016, including Windows 10, Windows 11, Windows Server 2016, Windows Server 2019, and Windows Server 2022.
Technical Details
The security update modifies several core components of Microsoft Word 2016:
Updated Components
- winword.exe: The main Word application executable, updated to version 16.0.5435.1000
- wwlib.dll: Core Word library containing document processing routines
- msword.olb: Word object library for macro and automation support
- mso.dll: Microsoft Office shared library with common functionality
Security Enhancements
The update implements several security improvements:
- Enhanced Input Validation: Improved validation of document elements and properties before processing
- Memory Protection: Better memory initialization and bounds checking to prevent information disclosure
- Macro Security: Strengthened enforcement of macro execution policies
- Error Handling: Improved error handling for malformed documents to prevent crashes and unexpected behavior
Installation Requirements
Before installing KB5002848, ensure your system meets the following requirements:
- Microsoft Office 2016 installed (any edition or standalone Word 2016)
- 45 MB of available disk space for temporary installation files
- Administrative privileges on the target system
- All Office applications closed during installation
No prerequisite updates are required for this security update. However, it is recommended to have the latest Windows updates installed to ensure optimal compatibility.
Deployment Considerations
Enterprise administrators should consider the following when deploying this update:
Testing Recommendations
- Test the update in a controlled environment before widespread deployment
- Verify compatibility with critical business documents and templates
- Test third-party Word add-ins and macros for continued functionality
- Validate document workflows and automated processes
Deployment Methods
- WSUS: Deploy through Windows Server Update Services for centralized management
- SCCM: Use System Center Configuration Manager for enterprise deployment
- Intune: Deploy through Microsoft Intune for cloud-managed devices
- Group Policy: Configure automatic updates through Group Policy settings
Post-Installation Verification
After installing the update, verify successful installation using one of these methods:
Get-HotFix -Id KB5002848Or check the Office update history:
- Open any Office 2016 application
- Go to File > Account
- Click Update Options > View Updates
- Verify
KB5002848appears in the installed updates list
Security Impact
Installing this update significantly improves the security posture of Word 2016 installations by:
- Preventing remote code execution attacks through malicious documents
- Protecting against information disclosure vulnerabilities
- Strengthening macro security enforcement
- Improving overall application stability and reliability
Important: Organizations should prioritize installation of this update due to the critical nature of the vulnerabilities addressed. Delaying installation leaves systems vulnerable to potential attacks through malicious Word documents.
Frequently Asked Questions
What does KB5002848 resolve?
KB5002848 resolves multiple security vulnerabilities in Microsoft Word 2016, including remote code execution flaws in the document parsing engine, information disclosure vulnerabilities in memory handling, and macro security bypass issues. The update strengthens Word's security against malicious documents and improves overall application stability.
Which systems require KB5002848?
KB5002848 is required for all installations of Microsoft Office 2016 and standalone Word 2016, including both 32-bit and 64-bit editions. The update applies to systems running Windows 10, Windows 11, and supported Windows Server versions that have Office 2016 installed.
Is KB5002848 a security update?
Yes, KB5002848 is a critical security update that addresses multiple vulnerabilities in Word 2016. These include remote code execution vulnerabilities that could allow attackers to run malicious code through specially crafted documents, and information disclosure flaws that could expose sensitive data.
What are the prerequisites for KB5002848?
KB5002848 requires Microsoft Office 2016 or standalone Word 2016 to be installed, 45 MB of available disk space, and administrative privileges for installation. No prerequisite updates are required, but all Office applications should be closed before installation begins.
Are there known issues with KB5002848?
Some users may experience minor document formatting changes with very old Word documents, compatibility issues with third-party add-ins that use undocumented APIs, and slightly longer document opening times due to enhanced security validation. Most issues can be resolved by updating add-ins or converting old documents to newer formats.
References (3)
1
Guide de mise à jour de sécurité MicrosoftInformations officielles sur les mises à jour de sécurité Microsoft et détails sur les vulnérabilitéshttps://msrc.microsoft.com/update-guide/
2Historique des mises à jour d'Office 2016Historique complet des mises à jour pour les produits Microsoft Office 2016https://docs.microsoft.com/en-us/officeupdates/update-history-office-2016
3Catalogue Microsoft UpdateCentre de téléchargement pour les mises à jour Microsoft, y compris KB5002848https://catalog.update.microsoft.com/
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