CVE-2020-1501 in SharePoint Foundation
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-2020-1501 represents a critical spoofing flaw within Microsoft SharePoint Server that stems from inadequate input sanitization mechanisms. This weakness exists in the server's handling of specially crafted web requests, creating an exploitable condition that allows authenticated attackers to manipulate the system's request processing behavior. The vulnerability specifically targets the SharePoint Server's validation routines, which fail to properly sanitize user-supplied data before processing, thereby enabling malicious input to be interpreted as legitimate commands. The flaw operates at the application layer and demonstrates a failure in the server's security controls to validate and sanitize incoming web requests, creating a pathway for unauthorized manipulation of the system's operational behavior.
The technical exploitation of this vulnerability enables attackers to execute cross-site scripting attacks through carefully crafted web requests that bypass the server's normal input validation procedures. When successfully exploited, the vulnerability allows attackers to execute scripts within the security context of authenticated users, effectively elevating their privileges to match those of the compromised user. This creates a dangerous escalation path where attackers can perform actions that would normally be restricted to authorized users, including reading unauthorized content, modifying permissions, deleting documents, and injecting malicious scripts into user browsers. The security context of the current user becomes a critical factor in the exploitation process, as the malicious scripts execute with the same permissions and access rights as the legitimate user, potentially leading to comprehensive system compromise.
The operational impact of CVE-2020-1501 extends beyond simple data theft or modification, as it enables sophisticated attack patterns that can lead to complete system compromise. Attackers can leverage this vulnerability to establish persistent access to SharePoint environments, potentially using the compromised server as a foothold for broader network infiltration. The ability to read unauthorized content creates significant data exposure risks, while the permission modification capabilities allow attackers to alter access controls and potentially escalate their access to administrative levels. Browser-based injection attacks pose additional threats by enabling attackers to compromise user sessions and potentially harvest credentials or sensitive information from unsuspecting users. This vulnerability particularly affects organizations that rely heavily on SharePoint for document management and collaboration, as it can be exploited to gain unauthorized access to sensitive corporate information.
Microsoft's security update for CVE-2020-1501 addresses the root cause by implementing enhanced input sanitization procedures that properly validate and sanitize web requests before processing. The fix ensures that SharePoint Server applies consistent and robust validation mechanisms to all incoming requests, preventing malicious input from being interpreted as valid commands. This remediation aligns with industry standards such as CWE-79, which addresses cross-site scripting vulnerabilities, and follows the ATT&CK framework's techniques for command and control operations and credential access. Organizations should implement this security update immediately to prevent exploitation, while also considering additional defensive measures such as network segmentation, web application firewalls, and enhanced monitoring of SharePoint server activities. The vulnerability underscores the importance of proper input validation and sanitization in web applications, particularly in enterprise collaboration platforms where user-generated content processing creates inherent security risks that must be carefully managed through robust security controls.