CVE-2026-70355
Summary
by MITRE • 08/11/2026
Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Office SharePoint allows an authorized attacker to elevate privileges over a network.
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Analysis
by VulDB Data Team • 08/11/2026
Cross-site scripting vulnerabilities in Microsoft Office SharePoint represent a critical security weakness that enables authenticated attackers to exploit input validation flaws during web page generation processes. This vulnerability specifically manifests when the system fails to properly sanitize user-supplied data before incorporating it into dynamically generated web content, creating opportunities for malicious script injection attacks. The flaw operates at the application layer where user inputs are processed and rendered without adequate neutralization measures, allowing attackers to execute arbitrary scripts within the context of other users' sessions.
The technical implementation of this vulnerability stems from insufficient input validation mechanisms within SharePoint's web page generation framework. When authorized users submit content or interact with web forms, the system should employ robust sanitization techniques to prevent malicious payloads from being stored or executed. However, the improper neutralization allows attackers to inject malicious scripts that can persist in the application's database or memory. This weakness creates a persistent threat vector where legitimate user sessions become compromised as the injected scripts execute within the browser context of other authenticated users.
From an operational perspective, this vulnerability enables privilege escalation attacks by allowing attackers to manipulate the SharePoint environment through script injection techniques. The attacker can leverage their authorized status to craft malicious payloads that exploit the XSS flaw, potentially gaining elevated privileges or accessing sensitive data. The impact extends beyond simple script execution as it can facilitate session hijacking, data theft, and further exploitation within the network infrastructure. This vulnerability particularly affects organizations relying on SharePoint for collaborative environments where users frequently submit content and interact with web-based interfaces.
The security implications align with CWE-79 which specifically addresses cross-site scripting vulnerabilities in input validation and output encoding processes. Attackers can utilize techniques described in the ATT&CK framework under T1059.001 for command and script injection, leveraging the SharePoint environment to execute malicious code. Organizations should implement comprehensive input sanitization measures including proper HTML escaping, content security policies, and regular security assessments of web application components. Mitigation strategies include enforcing strict input validation controls, implementing robust output encoding mechanisms, and maintaining up-to-date security patches. Additionally, network segmentation and privileged access controls can reduce the potential impact of successful exploitation attempts while monitoring systems should be deployed to detect anomalous script injection patterns within SharePoint environments.