Critical Zero-Day Vulnerability in Microsoft SharePoint Exploited

On July 20, 2025, cybersecurity experts are sounding alarms over a critical zero-day vulnerability (CVE-2025-53770) in Microsoft SharePoint. This flaw affects on-premises installations of SharePoint Server, allowing attackers to execute remote code without authentication through deserialization issues. Microsoft has acknowledged the threat and is working on a patch. In the interim, organizations are urged to implement mitigation strategies, such as configuring Antimalware Scan Interface (AMSI) integration to help block potential exploits. The Cybersecurity and Infrastructure Security Agency (CISA) has added this vulnerability to its Known Exploited Vulnerabilities Catalog, citing evidence of widespread exploitation across various sectors. Over 75 organizations, including government and private entities, are reportedly impacted, raising significant concerns about public and private infrastructure security. Immediate action is essential to prevent unauthorized access and protect sensitive data.

Also In Security Today

• CISA Advisory: CISA's recent advisory emphasizes the need for organizations to prioritize remediation of CVE-2025-53770, reinforcing the urgency of addressing this critical vulnerability. Read more.
• Ransomware Threats Rise: The SafePay ransomware group has targeted Ingram Micro, causing significant operational disruptions. Organizations are advised to bolster their defenses against ransomware attacks. Read more.
• Vulnerability Impact: The widespread exploitation of CVE-2025-53770 has affected over 75 organizations, underscoring the extensive reach of this vulnerability across both government and private sectors. Learn more.

Analyst's Take

Today's developments highlight an escalating trend in cyber threats, particularly zero-day vulnerabilities that are quickly exploited. Organizations must prioritize patching and employ layered security measures, including regular vulnerability assessments and employee training. The rise in ransomware incidents further emphasizes the importance of robust incident response plans. Cybersecurity professionals should stay informed and proactive, adopting a risk management approach to defend against evolving threats.

CVE Details: CVE-2025-53770, CVSS Score: 9.8 (Critical)