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🔥 This vulnerability is being actively exploited in the wild (CISA Known Exploited Vulnerabilities catalog)

CVE-2026-50522: Microsoft SharePoint Deserialization of Untrusted Data Vulnerability

highvulnerability🔥 Actively Exploited

security

Source: CISA Known Exploited VulnerabilitiesJuly 21, 2026CVE-2026-50522

Summary

Microsoft SharePoint has a deserialization of untrusted data vulnerability (a flaw where the software unsafely processes data from untrusted sources, potentially allowing attackers to run malicious code). An unauthorized attacker could exploit this over a network to execute code on affected systems. This vulnerability is currently being actively exploited in real-world attacks.

Solution / Mitigation

Apply mitigations in accordance with vendor instructions from Microsoft, following CISA's BOD 26-04 guidance for prioritizing security updates based on risk. For cloud services, follow applicable BOD 26-04 guidance or discontinue use of the product if mitigations are unavailable. Stakeholders must evaluate each system's internet exposure and ensure adherence to BOD 26-04 patching guidelines by the due date of 2026-07-25. See Microsoft Security Response Center (https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50522) for specific vendor instructions.