CVE-2025-30382: Untrusted Data Deserialization Vulnerability in Microsoft Office SharePoint

Overview

The CVE-2025-30382 is a serious vulnerability that affects Microsoft Office SharePoint, a widely used web application platform for businesses around the globe. It involves the deserialization of untrusted data, which can allow an unauthorized attacker to execute code locally. Given SharePoint’s integral role in many business operations, this vulnerability poses a significant security risk. If exploited, this vulnerability could potentially compromise entire systems or lead to data leakage. Therefore, it is critical to understand this vulnerability, its potential impacts, and how to mitigate it.

Vulnerability Summary

CVE ID: CVE-2025-30382
Severity: High (7.8)
Attack Vector: Local
Privileges Required: None
User Interaction: Required
Impact: System compromise or data leakage

Affected Products

Product | Affected Versions

Microsoft Office SharePoint | All versions prior to patch

How the Exploit Works

The exploit takes advantage of a flaw in the way Microsoft Office SharePoint handles data deserialization. Deserialization is the process of converting serialized data back into its original form. However, if an attacker can inject untrusted data into the deserialization process, they can potentially alter the normal execution flow or execute arbitrary code. In this case, the attacker needs to convince a user to open a malicious SharePoint file, which triggers the deserialization of the untrusted data and subsequently allows the attacker to execute code locally.

Conceptual Example Code

Here is a conceptual example of how an attacker might exploit this vulnerability. The attacker could embed malicious code in a SharePoint file and send it to a user. When the user opens the file, the deserialization process is triggered, executing the malicious code.

POST /sharepoint/openfile HTTP/1.1
Host: target.example.com
Content-Type: application/json
{ "file": "malicious_file.sharepoint" }

In this example, `malicious_file.sharepoint` is a SharePoint file containing the malicious payload.
Please note that this is a simplified, hypothetical example and actual exploits may be more complex.

Mitigation Guidance

To mitigate this vulnerability, users are urged to apply the vendor patch as soon as it becomes available. Until then, users can use a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) as temporary mitigation. These systems can help to detect and prevent potential attacks. Regularly updating and patching software is also a good practice to enhance security and protect against vulnerabilities.