CVE-2025-47994 is a high-severity vulnerability identified in Microsoft Office 2019 (version 19.0.0) involving the deserialization of untrusted data, classified under CWE-502. Deserialization vulnerabilities occur when an application deserializes data from untrusted sources without sufficient validation, allowing attackers to manipulate the serialized data to execute arbitrary code or escalate privileges. In this case, the vulnerability allows an unauthorized attacker to locally elevate privileges by exploiting the deserialization process within Microsoft Office 2019. The CVSS 3.1 base score is 7.8, indicating a high impact, with the vector string CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C. This means the attack requires local access (AV:L), low attack complexity (AC:L), no privileges required (PR:N), but user interaction is needed (UI:R). The scope remains unchanged (S:U), and the impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H). The exploitability is official (E:U), remediation level is official fix available (RL:O), and report confidence is confirmed (RC:C). No known exploits are currently in the wild, and no patch links were provided at the time of publication. The vulnerability could be triggered by a maliciously crafted file or data input that Microsoft Office 2019 processes, leading to unauthorized privilege escalation on the local system. This could allow attackers to bypass security restrictions, execute arbitrary code with elevated privileges, and potentially compromise the affected system fully.

For European organizations, this vulnerability poses a significant risk, especially in environments where Microsoft Office 2019 is widely deployed on user endpoints. The ability to elevate privileges locally can enable attackers who have gained limited access—such as through phishing or malicious documents—to escalate their permissions and move laterally within networks. This can lead to data breaches, intellectual property theft, disruption of business operations, and potential compliance violations under regulations such as GDPR. Organizations in sectors with high regulatory scrutiny or critical infrastructure may face increased risks due to the potential for attackers to gain administrative control on affected machines. The requirement for user interaction (opening a malicious file) means social engineering remains a key attack vector. However, once exploited, the high impact on confidentiality, integrity, and availability can result in severe operational and reputational damage.

To mitigate this vulnerability effectively, European organizations should: 1) Prioritize applying official patches or updates from Microsoft as soon as they become available, even though no patch links were provided at the time of this report. 2) Implement strict endpoint protection measures that include behavior-based detection to identify suspicious deserialization activities or privilege escalation attempts. 3) Enforce application whitelisting and restrict execution of unauthorized or untrusted Office macros and scripts. 4) Educate users on the risks of opening unsolicited or suspicious Office documents, emphasizing the importance of verifying sources before enabling content. 5) Utilize network segmentation to limit the spread of an attacker who gains elevated privileges on a local machine. 6) Employ least privilege principles on user accounts to reduce the impact of privilege escalation. 7) Monitor logs and endpoint telemetry for unusual privilege escalation events or anomalous Office application behavior. These targeted measures go beyond generic advice by focusing on proactive patch management, user awareness, and advanced detection tailored to the nature of this deserialization vulnerability.