CVE-2020-0893 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-2020-0894.
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Analysis
by VulDB Data Team • 05/12/2025
The vulnerability identified as CVE-2020-0893 represents a critical cross-site scripting flaw within Microsoft SharePoint Server that stems from inadequate input sanitization mechanisms. This weakness allows attackers to inject malicious scripts into web requests that are processed by the affected server, creating a persistent security risk for organizations relying on SharePoint infrastructure. The vulnerability specifically manifests when SharePoint Server fails to properly validate and sanitize user-supplied input within web requests, enabling attackers to execute arbitrary JavaScript code in the context of victim sessions.
The technical exploitation of this XSS vulnerability occurs through the manipulation of web request parameters that SharePoint Server processes without adequate sanitization. Attackers can craft malicious payloads that, when executed, can steal session cookies, redirect users to malicious sites, or perform actions on behalf of authenticated users. The flaw exists at the input validation layer where SharePoint Server does not sufficiently filter or escape special characters that could be interpreted as executable script code. This allows attackers to inject script tags or other malicious code that persists in the server's response to subsequent requests.
The operational impact of CVE-2020-0893 extends beyond simple script execution, as it can enable attackers to establish persistent access to SharePoint environments and potentially escalate privileges within the organization's web infrastructure. Once exploited, the vulnerability can facilitate session hijacking attacks, data exfiltration, and serve as a foothold for further reconnaissance and lateral movement within the network. The vulnerability affects multiple versions of SharePoint Server and can be particularly dangerous in enterprise environments where SharePoint serves as a central collaboration platform for sensitive business data and internal communications.
Organizations should implement comprehensive mitigation strategies including immediate patch deployment from Microsoft, web application firewalls configured to detect and block XSS patterns, and enhanced input validation across all SharePoint web applications. The vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws in web applications, and maps to ATT&CK technique T1059.007 for scripting languages and T1566 for social engineering tactics that attackers often employ to exploit such vulnerabilities. Additional protective measures include enabling SharePoint's built-in security features, implementing strict content security policies, and conducting regular security assessments of web applications to identify similar sanitization weaknesses.