CVE-2025-53771 is a path traversal vulnerability identified in Microsoft SharePoint Enterprise Server 2016. This vulnerability arises due to improper limitation of a pathname to a restricted directory, classified under CWE-22. Path traversal vulnerabilities allow an attacker to manipulate file paths to access files and directories outside the intended restricted directory. In this case, an authorized attacker—meaning one with some level of legitimate access—can exploit this flaw to perform spoofing attacks over a network. Spoofing here likely refers to the attacker tricking the system or users into accepting malicious content or requests as legitimate by leveraging unauthorized file access. The vulnerability requires low attack complexity (AC:L) but does require privileges (PR:L) and user interaction (UI:R). The CVSS 3.1 base score is 6.3, indicating a medium severity level. The impact on confidentiality is high (C:H), meaning sensitive information could be exposed, while integrity impact is low (I:L), and availability is not affected (A:N). The scope remains unchanged (S:U), so the vulnerability affects the vulnerable component only. The vulnerability does not currently have known exploits in the wild and no patches have been linked yet. The flaw is specific to Microsoft SharePoint Enterprise Server 2016, a widely used collaboration and document management platform in enterprises. Given the nature of SharePoint as a repository for sensitive corporate data and its integration with other Microsoft services, exploitation could lead to unauthorized disclosure of confidential information and potential further attacks leveraging the spoofed content or access.

For European organizations, the impact of this vulnerability could be significant, especially for those relying heavily on Microsoft SharePoint Enterprise Server 2016 for document management and collaboration. Confidentiality breaches could expose sensitive corporate data, intellectual property, or personal data protected under GDPR, leading to regulatory penalties and reputational damage. The spoofing capability could facilitate phishing or social engineering attacks within the organization, increasing the risk of credential theft or lateral movement by attackers. Since the vulnerability requires authorized access and user interaction, insider threats or compromised user accounts could be leveraged to exploit this flaw. The lack of impact on availability reduces the risk of service disruption but does not diminish the risk of data leakage. European organizations in sectors such as finance, healthcare, government, and critical infrastructure, which often use SharePoint for sensitive information sharing, are particularly at risk. The medium severity rating suggests that while the vulnerability is not the most critical, it still demands timely attention to prevent exploitation.

To mitigate this vulnerability, European organizations should: 1) Immediately review and restrict SharePoint user permissions to the minimum necessary, ensuring that only trusted users have access to sensitive directories and files. 2) Monitor and audit SharePoint access logs for unusual file access patterns that could indicate exploitation attempts. 3) Implement strict input validation and sanitization on any custom SharePoint extensions or web parts that handle file paths to prevent path traversal attempts. 4) Educate users about the risks of interacting with suspicious links or content within SharePoint to reduce the likelihood of successful spoofing attacks. 5) Apply any forthcoming security patches from Microsoft as soon as they become available. 6) Consider deploying network-level protections such as web application firewalls (WAFs) configured to detect and block path traversal payloads targeting SharePoint endpoints. 7) Use multi-factor authentication (MFA) to reduce the risk of compromised credentials being used to exploit this vulnerability. 8) Regularly back up SharePoint data to enable recovery in case of data compromise.