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Attackers exploit critical SharePoint flaw after PoC goes public (CVE-2026-55040)

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Attackers exploit critical SharePoint flaw after PoC goes public (CVE-2026-55040)

A critical authentication bypass vulnerability in Microsoft SharePoint (CVE-2026-55040) has entered active exploitation after Rapid7 released proof-of-concept code. The flaw, patched in July 2026 Patch Tuesday updates, permits attackers to impersonate users, disclose files, and modify data without affecting system availability.

Why it matters: Organizations running unpatched SharePoint installations are immediately at risk of unauthorized file access and data modification by attackers leveraging now-public exploit code; apply July 2026 patches urgently.

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vulnerabilities

Attackers exploit critical SharePoint flaw after PoC goes public (CVE-2026-55040)

A critical authentication bypass vulnerability in Microsoft SharePoint (CVE-2026-55040) has entered active exploitation after Rapid7 released proof-of-concept code. The flaw, patched in July 2026 Patch Tuesday updates, permits attackers to impersonate users, disclose files, and modify data without affecting system availability.

Why it matters: Organizations running unpatched SharePoint installations are immediately at risk of unauthorized file access and data modification by attackers leveraging now-public exploit code; apply July 2026 patches urgently.

VendorsMicrosoft
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