CVE-2026-62826 in SharePoint Server
Summary
by MITRE • 07/17/2026
Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Office SharePoint allows an authorized attacker to perform spoofing over a network.
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Analysis
by VulDB Data Team • 07/17/2026
Cross-site scripting vulnerabilities in Microsoft Office SharePoint represent a critical security weakness that stems from inadequate input validation during web page generation processes. This vulnerability falls under the CWE-79 category, which specifically addresses cross-site scripting flaws where malicious scripts are injected into otherwise trusted websites. The flaw occurs when SharePoint fails to properly sanitize user-supplied input before incorporating it into dynamically generated web content, creating an environment where attackers can execute malicious code within the context of other users' browsers.
The technical implementation of this vulnerability exploits the web application's failure to neutralize potentially dangerous characters and sequences in user input fields. Attackers can leverage this weakness by submitting malicious payloads through various SharePoint interfaces including document libraries, discussion boards, or form fields that are subsequently rendered in web pages. When legitimate users access these compromised pages, their browsers execute the injected scripts which can perform actions such as stealing session cookies, modifying page content, redirecting users to malicious sites, or executing unauthorized operations within the SharePoint environment.
The operational impact of this vulnerability extends beyond simple data theft, as it enables sophisticated attack vectors that can compromise entire SharePoint deployments. Authorized attackers with minimal privileges can exploit this weakness to perform session hijacking attacks, where stolen authentication tokens allow them to impersonate legitimate users and gain access to sensitive information or administrative functions. The vulnerability also supports more advanced techniques such as credential harvesting through JavaScript-based keyloggers or exploitation of other browser vulnerabilities through the initial XSS payload. This makes SharePoint environments particularly attractive targets for attackers seeking persistent access to corporate networks.
Mitigation strategies should focus on implementing comprehensive input validation and output encoding mechanisms throughout the SharePoint application stack. Organizations must ensure that all user inputs are properly sanitized using whitelisting approaches rather than blacklisting methods, which can be bypassed through creative attack techniques. The implementation of Content Security Policies (CSP) provides an additional layer of protection by restricting script execution within SharePoint pages, while also implementing proper HTTP headers such as X-Content-Type-Options and X-Frame-Options to prevent certain classes of exploitation. Regular security updates and patches from Microsoft should be applied promptly, with organizations monitoring vulnerability databases for related threats that may exploit similar weaknesses in SharePoint components. Additionally, implementing Web Application Firewalls (WAF) with rules specifically designed to detect and block XSS patterns can provide effective protection against these attacks while maintaining operational functionality.
The attack surface for this vulnerability aligns with ATT&CK technique T1059.007 for script injection and T1566 for credential access through social engineering vectors that leverage the trust relationship between users and SharePoint applications. Organizations should also consider implementing user behavior analytics to detect anomalous activity patterns that may indicate exploitation attempts, particularly around unusual data access or modification activities in SharePoint environments.