<p>This vulnerability is caused when SharePoint Server does not properly sanitize a specially crafted request to an affected SharePoint server.</p> <p>An authenticated attacker could exploit this vulnerability by sending a specially crafted request to an affected SharePoint server. The attacker who successfully exploited this 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 victim, such as change permissions, delete content, steal sensitive information (such as browser cookies) and inject malicious content in the browser of the victim.</p> <p>For this vulnerability to be exploited, a user must click a specially crafted URL that takes the user to a targeted SharePoint Web App site.</p> <p>In an email attack scenario, an attacker could exploit the vulnerability by sending an email message containing the specially crafted URL to the user of the targeted SharePoint Web App site and convincing the user to click the specially crafted URL.</p> <p>In a web-based attack scenario, an attacker would have to host a website that contains a specially crafted URL to the targeted SharePoint Web App site that is used to attempt to exploit these vulnerabilities. In addition, compromised websites and websites that accept or host user-provided content could contain specially crafted content that could exploit the vulnerability. An attacker would have no way to force users to visit a specially crafted website. Instead, an attacker would have to convince them to visit the website, typically by getting them to click a link in an instant messenger or email message that takes them to the attacker's website, and then convince them to click the specially crafted URL.</p> <p>The security update addresses the vulnerability by helping to ensure that SharePoint Server properly sanitizes user web requests.</p>
| Software | From | Fixed in |
|---|---|---|
| microsoft / sharepoint_foundation | 2013-sp1 | 2013-sp1.x |
| microsoft / sharepoint_enterprise_server | 2016 | 2016.x |
| microsoft / sharepoint_server | 2019 | 2019.x |
A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.
CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.
A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.
Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.
Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.
SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.