CVE-2021-24072 in SharePoint
Summary
by MITRE • 02/26/2021
Microsoft SharePoint Server Remote Code Execution Vulnerability
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Analysis
by VulDB Data Team • 06/29/2026
Microsoft SharePoint Server contains a critical remote code execution vulnerability that stems from improper input validation in the server-side rendering functionality. This flaw allows attackers to execute arbitrary code on affected systems with the privileges of the SharePoint service account, creating a severe escalation path for malicious actors who can leverage this weakness to compromise entire enterprise environments. The vulnerability resides in how SharePoint processes certain HTTP requests containing specially crafted payloads that bypass normal security controls and trigger unintended code execution within the server context.
The technical implementation of this vulnerability involves a combination of input sanitization failures and unsafe object deserialization patterns that have been documented under CWE-20 and CWE-502 categories. Attackers can exploit this weakness by sending malicious requests that contain encoded payloads designed to manipulate SharePoint's rendering engine into executing unintended operations. The flaw specifically affects SharePoint Server versions 2016, 2019, and Microsoft 365, with the attack surface extending across multiple deployment scenarios including on-premises installations and hybrid environments where SharePoint integrates with other Microsoft services.
Operational impact of this vulnerability extends far beyond simple code execution capabilities, as it provides attackers with persistent access to corporate data repositories and enables lateral movement throughout network infrastructures. Organizations utilizing SharePoint for document management, collaboration platforms, and enterprise portals face significant risk exposure since the vulnerability can be exploited without authentication in many scenarios. The attack vector typically involves web-based exploitation through HTTP requests that trigger the vulnerable code path, allowing threat actors to establish command and control channels, exfiltrate sensitive data, or deploy additional malware payloads within the compromised environment.
Security mitigations for this vulnerability should include immediate deployment of Microsoft security patches and updates released through the regular patching cycle. Organizations must also implement network segmentation controls to limit access to SharePoint servers and deploy web application firewalls that can detect and block malicious payloads targeting this specific vulnerability. Additional defensive measures involve monitoring for unusual HTTP request patterns and implementing strict input validation policies across all SharePoint services. According to ATT&CK framework category T1203, this vulnerability represents a significant technique for initial access and privilege escalation within enterprise environments, making it a critical target for both preventive security controls and incident response preparedness measures that align with NIST cybersecurity framework recommendations.