CVE-2025-49697 is a heap-based buffer overflow vulnerability identified in Microsoft Office 2019, specifically version 19.0.0. This vulnerability, classified under CWE-122, allows an unauthorized attacker to execute arbitrary code locally on the affected system without requiring any user interaction or prior authentication. The flaw arises due to improper handling of memory buffers on the heap, which can be exploited by crafting malicious Office documents that, when opened, trigger the overflow. This overflow can overwrite critical memory regions, enabling the attacker to gain control over the execution flow, potentially leading to full compromise of the affected system. The vulnerability has a CVSS v3.1 base score of 8.4, indicating a high severity level, with impacts on confidentiality, integrity, and availability. The attack vector is local (AV:L), meaning the attacker must have local access to the system, but no privileges or user interaction are required (PR:N/UI:N). The scope remains unchanged (S:U), and the exploitability is considered official (RL:O) with confirmed remediation (RC:C). As of the published date, no known exploits are reported in the wild, but the critical nature of the vulnerability necessitates prompt attention. The absence of available patches at the time of reporting increases the risk window for organizations using the affected Microsoft Office version.

For European organizations, the impact of this vulnerability can be significant, especially in sectors where Microsoft Office 2019 is widely deployed, such as government, finance, healthcare, and critical infrastructure. Successful exploitation could lead to unauthorized code execution, enabling attackers to install malware, steal sensitive data, or disrupt business operations. Since the vulnerability requires local access, insider threats or attackers who gain initial foothold through other means could leverage this flaw to escalate privileges or move laterally within networks. The high impact on confidentiality, integrity, and availability means that sensitive European data protected under regulations like GDPR could be exposed or manipulated, leading to legal and reputational consequences. Additionally, the lack of user interaction requirement increases the risk of automated or stealthy attacks once local access is obtained. The absence of known exploits currently provides a limited window for mitigation before potential exploitation in the wild.

European organizations should prioritize the following specific mitigation steps: 1) Immediately inventory and identify all systems running Microsoft Office 2019 version 19.0.0 to assess exposure. 2) Implement strict access controls and monitoring to limit local access to trusted users only, reducing the risk of unauthorized local exploitation. 3) Employ application whitelisting and endpoint detection and response (EDR) solutions to detect anomalous behavior indicative of exploitation attempts. 4) Until an official patch is released, consider deploying virtual desktop infrastructure (VDI) or sandbox environments for handling untrusted Office documents to contain potential attacks. 5) Educate users and administrators about the risk of opening suspicious documents, even though user interaction is not required for exploitation, as initial local access vectors often involve social engineering. 6) Regularly check for and apply security updates from Microsoft as soon as patches become available. 7) Conduct penetration testing and vulnerability assessments focusing on local privilege escalation paths to identify and remediate related weaknesses.