Microsoft SharePoint Server improper authorization

Summaryinfo

A vulnerability, which was classified as problematic, was found in Microsoft SharePoint Server. This issue affects some unknown processing. Such manipulation leads to improper authorization. This vulnerability is referenced as CVE-2026-55040. It is possible to launch the attack remotely. Furthermore, an exploit is available.

Detailsinfo

A vulnerability was found in Microsoft SharePoint Server (affected version not known). It has been rated as problematic. Affected by this issue is some unknown functionality. The manipulation with an unknown input leads to a improper authorization vulnerability. Using CWE to declare the problem leads to CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. Impacted is confidentiality. CVE summarizes:

Weak authentication in Microsoft Office SharePoint allows an unauthorized attacker to bypass a security feature over a network.

The advisory is shared for download at msrc.microsoft.com. This vulnerability is handled as CVE-2026-55040 since 06/16/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are unknown but an exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 08/18/2026). The MITRE ATT&CK project declares the attack technique as T1548.002.

It is declared as attacked. This issue was added on 08/18/2026 to the CISA Known Exploited Vulnerabilities Catalog with a due date of 08/21/2026:

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.

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• Groupware Software

Vendor

• Microsoft

Name

• SharePoint Server

License

• commercial

Website

• Vendor: https://www.microsoft.com/

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