What is CVE-2025-53770, the “ToolShell” Zero-Day Vulnerability?

On July 18, 2025, cybersecurity researchers uncovered a critical zero-day vulnerability impacting Microsoft SharePoint, known as CVE-2025-53770, or “ToolShell.” This exploit, categorized as an unauthenticated remote code execution (RCE) flaw, quickly became a nightmare scenario for many organizations. Over 100 entities, including government agencies, telecommunications providers, healthcare institutions, and energy companies, were compromised in a matter of days. 

*** This is a Security Bloggers Network syndicated blog from Cimcor Blog authored by cimcoradmin. Read the original post at: https://www.cimcor.com/blog/microsoft-sharepoint-toolshell-zeroday-cve202553770