CVE-2025-53736 is a buffer over-read vulnerability classified under CWE-126 affecting Microsoft SharePoint Enterprise Server 2016, specifically version 16.0.0. The flaw exists in the way Microsoft Office Word components handle memory buffers when processing certain data, leading to an over-read condition. This vulnerability allows an unauthorized attacker with local access to the system to read sensitive information beyond the intended buffer boundaries, potentially disclosing confidential data stored or processed within SharePoint. The vulnerability does not require any privileges or user interaction, making it easier to exploit if local access is obtained. The CVSS v3.1 score of 6.8 reflects a medium severity, with the attack vector being local (AV:L), low attack complexity (AC:L), no privileges required (PR:N), and no user interaction (UI:N). The impact affects confidentiality (partial data disclosure) and availability (potential service disruption), but not integrity. No known exploits have been reported in the wild, and no official patches have been released at the time of publication. The vulnerability was reserved on July 9, 2025, and published on August 12, 2025. Organizations running this specific SharePoint version should be aware of the risk of local data leakage and prepare to implement mitigations and patches once available.

For European organizations, this vulnerability poses a risk of unauthorized local disclosure of sensitive information within SharePoint environments, which could include confidential business data, intellectual property, or personal data protected under GDPR. The potential availability impact could disrupt SharePoint services, affecting collaboration and document management workflows critical to business operations. Since the attack requires local access, the threat is heightened in environments where endpoint security is weak or insider threats exist. The confidentiality breach could lead to compliance violations and reputational damage. Organizations in sectors such as finance, healthcare, government, and critical infrastructure that rely heavily on SharePoint for document management are particularly vulnerable. The lack of current exploits reduces immediate risk, but the absence of patches means the vulnerability remains open for future exploitation.

1. Restrict local access to SharePoint servers strictly to trusted administrators and users with a legitimate need. 2. Implement robust endpoint security controls including host-based intrusion detection and prevention systems to monitor for suspicious local activity. 3. Enforce strict access control policies and audit logs to detect unauthorized access attempts. 4. Isolate SharePoint servers in segmented network zones to reduce the risk of lateral movement. 5. Regularly review and harden SharePoint configurations and underlying OS security settings. 6. Prepare for rapid deployment of official patches or updates from Microsoft once released. 7. Educate administrators and users about the risks of local exploitation and insider threats. 8. Consider deploying application whitelisting and memory protection technologies to mitigate buffer over-read exploitation. 9. Conduct vulnerability scanning and penetration testing focused on local privilege escalation and information disclosure vectors.