Microsoft SharePoint Server deserialization

Summaryinfo

A vulnerability classified as critical has been found in Microsoft SharePoint Server. Affected by this issue is some unknown functionality. Performing a manipulation results in deserialization. This vulnerability is cataloged as CVE-2026-50522. It is possible to initiate the attack remotely. Furthermore, there is an exploit available.

Detailsinfo

A vulnerability, which was classified as critical, was found in Microsoft SharePoint Server (version now known). This affects some unknown processing. The manipulation with an unknown input leads to a deserialization vulnerability. CWE is classifying the issue as CWE-502. The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.

The advisory is shared at msrc.microsoft.com. This vulnerability is uniquely identified as CVE-2026-50522 since 06/04/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are unknown but an exploit is available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 07/23/2026).

It is declared as attacked. The CISA Known Exploited Vulnerabilities Catalog lists this issue since 07/22/2026 with a due date of 07/25/2026:

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BO

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the databases at EUVD (EUVD-2026-43767) and CERT Bund (WID-SEC-2026-2317). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

• Microsoft Excel
• Microsoft Word
• Microsoft PowerPoint
• Microsoft Office
• Microsoft SharePoint
• Microsoft SharePoint Server 2019
• Microsoft 365 Apps
• Microsoft Office Online Server
• Microsoft Office 365

Productinfo

Type

• Groupware Software

Vendor

• Microsoft

Name

• SharePoint Server

License

• commercial

Website

• Vendor: https://www.microsoft.com/

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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