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

Threat actors have begun exploiting a critical Microsoft SharePoint flaw following the release of proof-of-concept (PoC) exploit code by Rapid7. About CVE-2026-55040 Tracked as CVE-2026-55040, the vulnerability was patched by Microsoft as part of its July 2026 Patch Tuesday updates. “The authentication feature could be bypassed as this vulnerability allows impersonation,” Microsoft said.…

Summary written for cymesh.dev. The full article lives at Help Net Security.