Attackers Exploit SharePoint Authentication Bypass After Public PoC Release

Threat actors are taking advantage of a Microsoft SharePoint vulnerability that was recently disclosed. The vulnerability, which has a CVSS score of 9.1, allows for a critical security feature bypass due to weak authentication. It was addressed by Microsoft in its July 2026 Patch Tuesday updates. Exploitation efforts began after a proof-of-concept code was made public. The vulnerability is identified as CVE-2026-55040.