CVE-2025-47166: Critical Deserialization Vulnerability in Microsoft Office SharePoint

Overview

The cybersecurity landscape is riddled with a multitude of vulnerabilities that can lead to potential system compromise or data leakage. One such vulnerability, designated as CVE-2025-47166, has been identified in Microsoft Office SharePoint. This vulnerability stems from the deserialization of untrusted data, allowing an authorized attacker to execute code over a network. Notably, this vulnerability impacts numerous organizations worldwide that leverage SharePoint for their business operations. It is vital for these organizations to understand and address this critical security flaw to mitigate potential cyber threats.

Vulnerability Summary

CVE ID: CVE-2025-47166
Severity: Critical (8.8 CVSS Score)
Attack Vector: Network
Privileges Required: Low
User Interaction: Required
Impact: Potential system compromise or data leakage

Affected Products

Product | Affected Versions

Microsoft Office SharePoint | [Assumed all versions until specific data available]

How the Exploit Works

The exploit leverages the deserialization vulnerability in Microsoft Office SharePoint. Deserialization is the process of converting a stream of bytes back into a copy of the original object. In this case, an authorized attacker can insert malicious serialized data that, when deserialized, can execute arbitrary code. This is possible because SharePoint does not correctly validate or sanitize the serialized data it receives over the network.

Conceptual Example Code

The following is a conceptual representation of how the vulnerability might be exploited. This hypothetical HTTP request could be sent by an attacker to exploit the vulnerability:

POST /SharePoint/endpoint HTTP/1.1
Host: target.example.com
Content-Type: application/serialized-object
{ "serialized_object": "base64_encoded_malicious_object" }

In this case, `base64_encoded_malicious_object` represents a serialized object that contains malicious code. When the SharePoint server deserializes this object, it could potentially execute the embedded malicious code, leading to a system compromise or data leakage.

Mitigation Guidance

While Microsoft is likely to release a patch to address this vulnerability, organizations are advised to apply the vendor patch as soon as it is available. As an interim measure, organizations could employ a Web Application Firewall (WAF) or Intrusion Detection System (IDS) to detect and prevent exploitation attempts. Other best practices include restricting network access to the SharePoint server and regularly updating all software components.
Remember, staying informed about the latest cybersecurity threats and implementing appropriate security measures is crucial for maintaining a secure IT environment.