CVE-2026-50522 in SharePoint Server
Summary
by MITRE • 07/14/2026
Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.
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Analysis
by VulDB Data Team • 07/14/2026
This vulnerability represents a critical deserialization flaw that exists within Microsoft Office SharePoint platforms, enabling remote code execution through the manipulation of untrusted data inputs. The core technical issue stems from the application's failure to properly validate and sanitize data during the deserialization process, creating an attack surface where malicious actors can craft specially crafted payloads that, when processed by the vulnerable system, execute arbitrary code with the privileges of the affected service account. The vulnerability is categorized under CWE-502 as "Deserialization of Untrusted Data," which specifically addresses the dangerous practice of processing unverified data structures without proper security controls. This flaw operates at the intersection of several attack vectors including web application exploitation and privilege escalation techniques, making it particularly dangerous in enterprise environments where SharePoint systems often serve as central collaboration platforms with elevated access rights.
The operational impact of this vulnerability extends far beyond simple remote code execution, as successful exploitation can lead to complete system compromise and persistent access within the target network. Attackers can leverage this weakness to establish reverse shells, deploy additional malware, or perform lateral movement attacks against other systems connected to the same network infrastructure. The vulnerability's remote nature means that attackers do not require physical access to the system or prior authentication credentials to exploit it, making it particularly attractive for automated exploitation campaigns. From an attacker perspective, this represents a high-value target within enterprise environments because SharePoint servers typically host sensitive organizational data and often run with elevated privileges, potentially providing attackers with access to corporate databases, file shares, and other critical resources. The attack chain typically involves crafting malicious serialized objects that exploit the deserialization process, which can be delivered through various vectors including web forms, file uploads, or API endpoints within the SharePoint ecosystem.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term architectural improvements to prevent similar issues from occurring in the future. Organizations should implement strict input validation measures that filter or reject potentially malicious serialized data before it reaches the deserialization layer, leveraging principle of least privilege configurations to limit the impact of any successful exploitation attempts. The implementation of web application firewalls and runtime application self-protection mechanisms can provide additional layers of defense against such attacks. Security controls should also include monitoring for unusual deserialization activity and implementing proper sandboxing techniques that isolate potentially malicious code execution. According to ATT&CK framework, this vulnerability maps to multiple techniques including T1059.007 for remote code execution and T1210 for exploitation of remote services, while the remediation measures align with defensive strategies such as T1566 for phishing prevention and T1486 for data encryption. Organizations must also ensure that their SharePoint environments are regularly updated with security patches from Microsoft, as this vulnerability has been addressed through official security releases that specifically target the deserialization flaw in question.