CVE-2020-0894 in SharePoint Enterprise Server
Summary
by MITRE
A cross-site-scripting (XSS) vulnerability exists when Microsoft SharePoint Server does not properly sanitize a specially crafted web request to an affected SharePoint server, aka 'Microsoft Office SharePoint XSS Vulnerability'. This CVE ID is unique from CVE-2020-0893.
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Analysis
by VulDB Data Team • 05/12/2025
The vulnerability identified as CVE-2020-0894 represents a critical cross-site scripting flaw within Microsoft SharePoint Server that arises from inadequate input sanitization mechanisms. This weakness allows attackers to inject malicious scripts into web requests that are processed by the affected SharePoint server, potentially compromising user sessions and data integrity. The vulnerability specifically manifests when SharePoint Server fails to properly sanitize user-supplied input in web requests, creating an attack vector that can be exploited through crafted malicious payloads. The flaw affects multiple versions of Microsoft SharePoint Server and represents a significant security risk for organizations relying on SharePoint for collaborative document management and web content publishing.
This XSS vulnerability operates through the exploitation of improper validation and sanitization of user input within SharePoint's web request processing pipeline. When a malicious user crafts a specially designed web request containing malicious script code, the SharePoint server processes this input without adequate sanitization, allowing the injected scripts to execute in the context of other users' browsers. The vulnerability stems from insufficient data validation mechanisms that should normally filter or escape potentially dangerous characters and script tags from user-supplied content before it is rendered to end users. This type of flaw falls under the Common Weakness Enumeration category CWE-79, which specifically addresses Cross-Site Scripting vulnerabilities in web applications.
The operational impact of CVE-2020-0894 extends beyond simple script execution, potentially enabling attackers to perform session hijacking, steal sensitive user credentials, access restricted information, and manipulate SharePoint content. Attackers can leverage this vulnerability to create persistent malicious scripts that execute whenever affected users access SharePoint sites, leading to long-term compromise of the organization's collaboration platform. The attack surface is particularly concerning given that SharePoint servers typically host sensitive corporate data, user authentication mechanisms, and collaborative workspaces where multiple users interact with shared resources. Organizations may experience data breaches, unauthorized access to confidential documents, and potential lateral movement within their network infrastructure if this vulnerability is exploited successfully.
Mitigation strategies for CVE-2020-0894 should prioritize immediate implementation of Microsoft's security patches and updates as released through regular security bulletins. Organizations must ensure their SharePoint Server installations are running the latest security updates from Microsoft, which address the specific input sanitization flaws that enable this XSS attack. Additional protective measures include implementing comprehensive input validation mechanisms, deploying web application firewalls that can detect and block malicious script injection attempts, and configuring proper content security policies to restrict script execution within SharePoint environments. Security teams should also conduct thorough vulnerability assessments of their SharePoint deployments, monitor web traffic for suspicious patterns, and implement user education programs to recognize potential phishing attempts that might exploit this vulnerability. The ATT&CK framework categorizes this type of vulnerability under the T1059 technique for command and control through scripting, emphasizing the importance of preventing malicious script execution in web environments.