KB5002847 — Security Update for SharePoint Server 2019 Language Pack

Overview

KB5002847 is a critical security update released on March 10, 2026, for SharePoint Server 2019 Language Pack components. This update addresses multiple high-severity vulnerabilities that could allow remote code execution, elevation of privilege, cross-site scripting, and information disclosure attacks in multilingual SharePoint environments.

Security Vulnerabilities Addressed

This update resolves four distinct security vulnerabilities identified in SharePoint Server 2019 Language Pack components:

CVE-2026-0847: Remote Code Execution in Language Pack Web Parts

A critical vulnerability in language pack web part rendering allows authenticated attackers to execute arbitrary code on SharePoint servers. The vulnerability occurs when processing malicious multilingual content through language-specific web parts, potentially leading to complete server compromise.

CVE-2026-0848: Elevation of Privilege in Language Configuration

This vulnerability enables authenticated users to gain administrative privileges through improper access controls in language pack configuration interfaces. Attackers could exploit this flaw to modify multilingual site settings and gain unauthorized access to sensitive SharePoint resources.

CVE-2026-0849: Cross-Site Scripting in Localized UI Components

Multiple XSS vulnerabilities exist in SharePoint Server 2019 Language Pack user interface components. These flaws allow attackers to inject malicious scripts through localized error messages, navigation elements, and form controls, potentially compromising user sessions and stealing sensitive information.

CVE-2026-0850: Information Disclosure in Language Error Handling

Improper error handling in language pack components can expose sensitive system information through detailed error messages and diagnostic logs. This information could be used by attackers to plan more sophisticated attacks against SharePoint infrastructure.

Affected Systems

KB5002847 applies to the following SharePoint Server 2019 configurations:

Installation Requirements

Before installing KB5002847, administrators must ensure their SharePoint environment meets the following prerequisites:

System Requirements

• Operating System: Windows Server 2016 or Windows Server 2019
• SharePoint Version: SharePoint Server 2019 with Language Pack
• Disk Space: Minimum 500 MB free space on system drive
• Memory: At least 2 GB available RAM during installation
• Network: Internet connectivity for automatic updates (if applicable)

Service Dependencies

The following SharePoint services must be stopped before installation:

• SharePoint Timer Service
• SharePoint Administration Service
• SharePoint Search Host Controller Service
• SharePoint User Code Host Service

Backup Recommendations

Deployment Considerations

Production Environment Deployment

For production SharePoint farms, Microsoft recommends the following deployment approach:

1. Test Environment Validation: Install and test KB5002847 in a development or staging environment that mirrors the production configuration
2. Maintenance Window Planning: Schedule installation during planned maintenance windows to minimize user impact
3. Phased Rollout: For multi-server farms, install the update on one server at a time to maintain service availability
4. Monitoring: Monitor SharePoint services and multilingual functionality for 24-48 hours after installation

High Availability Considerations

In SharePoint farms with high availability configurations:

• Install updates on secondary servers first
• Verify functionality before updating primary servers
• Coordinate with load balancer configurations to manage traffic during updates
• Test failover scenarios after update completion

Post-Installation Verification

After installing KB5002847, perform the following verification steps:

Service Status Verification

Get-Service | Where-Object {$_.Name -like "*SharePoint*"} | Select-Object Name, Status

Language Pack Functionality Testing

• Verify multilingual site navigation functions correctly
• Test language-specific web parts and content rendering
• Confirm localized error messages display appropriately
• Validate search functionality for multilingual content

Security Configuration Review

• Review SharePoint permissions for language pack administration
• Verify access controls for multilingual site configuration
• Test authentication requirements for language-specific operations

Update Rollback

If issues occur after installing KB5002847, the update can be removed through the following methods:

Control Panel Method

1. Open Programs and Features in Control Panel
2. Click View installed updates
3. Locate KB5002847 in the list
4. Right-click and select Uninstall
5. Restart the server when prompted

PowerShell Method

Get-HotFix -Id KB5002847 | Remove-HotFix -Restart