CVE-2025-53734 is a use-after-free vulnerability identified in Microsoft Office Visio 2019, specifically version 19.0.0. This vulnerability arises when the program improperly manages memory, freeing an object but continuing to use the pointer referencing that memory. An attacker can exploit this flaw by convincing a user to open a specially crafted Visio file, triggering the use-after-free condition. This leads to arbitrary code execution within the context of the current user, potentially allowing the attacker to execute malicious code locally without requiring prior authentication or elevated privileges. The vulnerability affects confidentiality, integrity, and availability, as it can lead to full system compromise. The CVSS 3.1 base score is 7.8, with vector AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H, indicating local attack vector, low attack complexity, no privileges required, but user interaction needed, and high impact on confidentiality, integrity, and availability. No public exploits or patches are currently available, increasing the risk window. The vulnerability was reserved on July 9, 2025, and published on August 12, 2025. Given the widespread use of Microsoft Office 2019 in enterprise environments, this vulnerability represents a significant threat, especially where Visio is used for diagramming and documentation.

For European organizations, this vulnerability poses a significant risk due to the widespread deployment of Microsoft Office 2019, including Visio, across government, financial, industrial, and corporate sectors. Successful exploitation can lead to local code execution, enabling attackers to escalate privileges, install malware, exfiltrate sensitive data, or disrupt operations. The high impact on confidentiality, integrity, and availability means critical business processes and sensitive information could be compromised. The requirement for user interaction means phishing or social engineering campaigns could be leveraged to deliver malicious Visio files. The absence of known exploits currently provides a limited window for proactive defense, but the lack of patches means organizations must rely on mitigation strategies until updates are released. The threat is particularly acute for organizations with less mature endpoint security or those that allow macro-enabled or file-based content from untrusted sources.

1. Restrict or disable the use of Microsoft Visio 2019 where possible, especially in environments where users may receive files from untrusted sources. 2. Implement strict email filtering and attachment scanning to block or quarantine suspicious Visio files. 3. Educate users about the risks of opening unsolicited or unexpected Visio documents, emphasizing caution with files requiring interaction. 4. Employ application control or whitelisting to prevent unauthorized execution of malicious code spawned via this vulnerability. 5. Use endpoint detection and response (EDR) solutions to monitor for anomalous behavior indicative of exploitation attempts. 6. Regularly back up critical data and ensure recovery processes are tested to mitigate potential ransomware or destructive payloads. 7. Monitor Microsoft security advisories closely and apply patches immediately upon release. 8. Consider deploying sandboxing or virtualized environments for opening untrusted Visio files to contain potential exploits.