CVE-2020-1500 in SharePoint Enterprise Server
Summary
by MITRE
A spoofing vulnerability exists when Microsoft SharePoint Server does not properly sanitize a specially crafted web request to an affected SharePoint server. An authenticated attacker could exploit the vulnerability by sending a specially crafted request to an affected SharePoint server. The attacker who successfully exploited the vulnerability could then perform cross-site scripting attacks on affected systems and run script in the security context of the current user. These attacks could allow the attacker to read content that the attacker is not authorized to read, use the victim's identity to take actions on the SharePoint site on behalf of the user, such as change permissions and delete content, and inject malicious content in the browser of the user. The security update addresses the vulnerability by helping to ensure that SharePoint Server properly sanitizes web requests.
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Analysis
by VulDB Data Team • 02/23/2026
The vulnerability identified as CVE-2020-1500 represents a critical spoofing flaw within Microsoft SharePoint Server that stems from inadequate input sanitization mechanisms. This weakness allows authenticated attackers to craft malicious web requests that bypass the server's security controls, creating a pathway for sophisticated cross-site scripting attacks. The vulnerability specifically targets the server's handling of web requests, where insufficient validation permits malicious payloads to be processed and executed within the context of legitimate user sessions. The flaw operates at the application layer and directly impacts the integrity of SharePoint's security model, particularly concerning user authentication and authorization boundaries.
The technical exploitation of this vulnerability leverages the server's failure to properly sanitize incoming web requests, enabling attackers to inject malicious scripts that execute within the security context of authenticated users. When successfully exploited, the vulnerability permits attackers to perform a range of malicious activities including unauthorized content access, privilege escalation, and data manipulation. The malicious scripts can read sensitive information that users should not have access to, modify permissions, delete content, and inject additional malicious payloads into user browsers. This creates a persistent threat vector where attackers can maintain access and continue exploiting the system beyond the initial breach, effectively compromising the entire SharePoint environment's security posture.
The operational impact of CVE-2020-1500 extends beyond simple data theft to encompass complete system compromise and potential lateral movement within network environments. Organizations utilizing SharePoint Server become vulnerable to persistent threats where attackers can use the compromised systems as entry points for broader attacks. The vulnerability's classification aligns with CWE-79, which addresses cross-site scripting flaws, and follows attack patterns consistent with the ATT&CK framework's web application attack vectors. The security update provided by Microsoft addresses this vulnerability through enhanced web request sanitization mechanisms that validate and filter incoming requests before processing, thereby preventing malicious payloads from being executed within the server environment.
Organizations should implement immediate mitigations including applying the official Microsoft security patches, implementing additional network-level controls such as web application firewalls, and conducting thorough security assessments of their SharePoint environments. The vulnerability demonstrates the critical importance of input validation and sanitization in web applications, particularly those handling user authentication and authorization. Security teams should also consider implementing monitoring solutions that can detect anomalous request patterns and unauthorized access attempts, as the vulnerability can be exploited through legitimate user sessions. Regular security audits and penetration testing of SharePoint environments help identify additional weaknesses that could be exploited in conjunction with this vulnerability, ensuring comprehensive protection against sophisticated attack vectors.