[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$f9FNWjVl7waK0r3OGk68O36FN1ta-YzB6xA4dLrfjBx8":3},{"lesson":4},{"id":5,"slug":6,"article_id":7,"title":8,"body":9,"prevention":10,"framework_refs":11,"status":18,"created_at":19,"published_at":20,"article":21,"tags":25,"podcasts":38},"bce19383-700f-4b60-b7d0-4dddc8b67ae7","critical-sharepoint-zero-day-leaves-1300-servers-exposed-to-spoofing-attacks","0be83ab0-97b6-4664-a4d8-9c4c0b4915db","Critical SharePoint Zero-Day Leaves 1,300+ Servers Exposed to Spoofing Attacks","A zero-day spoofing vulnerability in Microsoft SharePoint servers was patched in April 2026, yet over 1,300 internet-facing servers remain unpatched and vulnerable to unauthenticated attacks. The flaw allows attackers to exploit improper input validation to perform network spoofing, compromising both confidentiality and integrity of affected systems. This incident highlights the critical gap between patch availability and deployment, especially for internet-exposed enterprise infrastructure. CISA's inclusion of this vulnerability in their Known Exploited Vulnerabilities catalog and the two-week federal patching mandate underscore the severity and active exploitation risk.","**Immediate actions:**\n- Apply the April 2026 SharePoint security updates to all affected servers immediately\n- Scan all internet-facing SharePoint instances to identify vulnerable systems\n- Implement temporary network controls to restrict access to unpatched servers\n\n**Long-term improvements:**\n- Establish automated patch management processes with emergency deployment capabilities\n- Maintain a comprehensive inventory of all SharePoint servers and their patch status\n- Implement network segmentation to isolate SharePoint servers from critical internal systems\n\n**Detection measures:**\n- Deploy continuous vulnerability scanning for all internet-facing assets\n- Monitor SharePoint access logs for suspicious authentication patterns or spoofing attempts\n- Set up alerts for new CVEs affecting SharePoint and other critical infrastructure components",[12,13,14,15,16,17],"CIS Control 7 (Continuous Vulnerability Management)","NIST SI-2 (Flaw Remediation)","CISA BOD 22-01","NIST CM-8 (Information System Component Inventory)","CIS Control 1 (Inventory and Control of Enterprise Assets)","NIST SC-7 (Boundary Protection)","published","2026-04-22T08:09:22.983053+00:00","2026-04-22T08:09:22.693+00:00",{"id":7,"url":22,"slug":23,"title":24},"https:\u002F\u002Fwww.bleepingcomputer.com\u002Fnews\u002Fsecurity\u002Fover-1-300-microsoft-sharepoint-servers-vulnerable-to-ongoing-attacks\u002F","over-1-300-microsoft-sharepoint-servers-vulnerable-to-spoofing-attacks-a79a0f","Over 1,300 Microsoft SharePoint servers vulnerable to spoofing attacks",[26,32],{"id":27,"name":28,"slug":29,"description":30,"color":31},"05757c8d-6b93-4194-b35d-7359e7d33b0e","Vulnerability Management","vulnerability-management","Missing scans, no risk prioritization","#fb923c",{"id":33,"name":34,"slug":35,"description":36,"color":37},"af7fce9e-1ce8-4156-93bc-09dcfbfdf29d","Patch Management","patch-management","Unpatched vulnerabilities, delayed updates","#ef4444",[]]