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Known CVE

Microsoft SharePoint Server - Authentication Bypass (ToolShell)

Microsoft Office SharePoint Server contains an improper authentication vulnerability that allows unauthorized attackers to perform spoofing over a network. By crafting a POST request to /_layouts/15/ToolPane.aspx with a forged Referer header (/_layouts/SignOut.aspx), attackers can bypass authentication mechanisms and gain unauthorized access to protected endpoints. This vulnerability is part of the ToolShell exploit chain and is a patch bypass for CVE-2025-49706. When chained with CVE-2025-53770 (deserialization vulnerability), it enables unauthenticated remote code execution on SharePoint Server.

CVE-2025-53771

Medium2025CVSS 6.5CWE-287

cve2025 · sharepoint · auth-bypass · microsoft · toolshell · vkev · vuln

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