CVE-2025-53736 is a buffer over-read vulnerability classified under CWE-126 affecting Microsoft SharePoint Enterprise Server 2016, version 16.0.0. The issue arises from improper bounds checking when processing Microsoft Office Word documents, allowing an attacker to read memory beyond the intended buffer limits. This can lead to unauthorized disclosure of sensitive information stored in memory, potentially exposing confidential data to local attackers. The vulnerability requires local access (AV:L), does not require privileges (PR:N), and no user interaction (UI:N) is needed, making it exploitable by any user with local system access. The scope is unchanged (S:U), meaning the impact is confined to the vulnerable component. The CVSS v3.1 base score is 6.8, indicating a medium severity level. The impact affects confidentiality (C:L) and availability (A:H) but not integrity (I:N). The availability impact suggests that exploitation might cause system instability or crashes. 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 in early July 2025 and published in August 2025. Given the nature of SharePoint as a collaboration and document management platform widely used in enterprises, this vulnerability could be leveraged by insiders or attackers who have gained local access to extract sensitive information from memory buffers during document processing.

For European organizations, especially those relying on Microsoft SharePoint Enterprise Server 2016 for document management and collaboration, this vulnerability poses a risk of sensitive information disclosure. The requirement for local access limits remote exploitation but increases the threat from insider attacks, compromised endpoints, or attackers who have gained physical or remote desktop access. The availability impact could disrupt SharePoint services, affecting business continuity. Organizations in sectors with strict data protection requirements, such as finance, healthcare, and government, could face compliance and reputational risks if sensitive data is exposed. The vulnerability could also be leveraged as part of a multi-stage attack to escalate privileges or move laterally within networks. Since no patches are currently available, organizations must rely on compensating controls to mitigate risk. The impact is heightened in environments where endpoint security and access controls are weak or where SharePoint servers are accessible to multiple users with local access privileges.

1. Restrict local access to SharePoint Enterprise Server 2016 systems to trusted personnel only, enforcing strict access controls and monitoring. 2. Implement endpoint security measures such as application whitelisting, behavior monitoring, and intrusion detection to detect suspicious local activities. 3. Use network segmentation to isolate SharePoint servers from general user workstations to reduce the risk of unauthorized local access. 4. Regularly audit and review user permissions and access logs to identify potential insider threats or unauthorized access attempts. 5. Disable or limit the use of Microsoft Office Word file processing on SharePoint servers where possible, or apply strict file validation policies. 6. Monitor Microsoft security advisories closely and apply official patches or updates immediately once released. 7. Employ memory protection technologies such as Data Execution Prevention (DEP) and Address Space Layout Randomization (ASLR) on SharePoint servers to reduce exploitation likelihood. 8. Educate users and administrators about the risks of local access vulnerabilities and enforce strong endpoint security hygiene.