CVE-2025-53730 is a high-severity use-after-free vulnerability (CWE-416) identified in Microsoft Office 2019, specifically affecting the Visio component. This vulnerability arises when the software improperly manages memory, allowing an attacker to exploit a freed memory region. In this case, an unauthorized attacker can trigger the use-after-free condition by crafting a malicious Visio file or document, which when opened or processed by the vulnerable Office 2019 Visio application, leads to execution of arbitrary code locally. The vulnerability requires local access (AV:L) and user interaction (UI:R), meaning the victim must open or interact with a malicious file. No privileges are required to exploit it (PR:N). The vulnerability impacts confidentiality, integrity, and availability (C:H/I:H/A:H), indicating that successful exploitation can lead to full system compromise, including code execution with the privileges of the user running the application. The CVSS 3.1 base score is 7.8, reflecting a high severity level. There are no known exploits in the wild yet, and no patches have been published at the time of this report. The vulnerability was reserved in early July 2025 and published in August 2025. The lack of a patch means that organizations using Microsoft Office 2019, particularly the Visio component, remain exposed until a fix is released and applied. Given the widespread use of Microsoft Office products in enterprise environments, this vulnerability represents a significant risk if exploited, especially in environments where users frequently exchange Visio files or use Visio for diagramming and documentation tasks.

For European organizations, the impact of CVE-2025-53730 can be substantial. Microsoft Office 2019 is widely deployed across various sectors including government, finance, healthcare, and critical infrastructure in Europe. An attacker exploiting this vulnerability could execute arbitrary code locally, potentially leading to data breaches, ransomware deployment, or lateral movement within corporate networks. The requirement for user interaction means phishing or social engineering campaigns could be used to deliver malicious Visio files. Confidentiality breaches could expose sensitive personal data protected under GDPR, leading to regulatory fines and reputational damage. Integrity and availability impacts could disrupt business operations, especially in sectors relying heavily on Office productivity tools. The absence of a patch increases the window of exposure, making timely detection and mitigation critical. Organizations with less mature endpoint protection or user awareness programs are at higher risk. Additionally, the vulnerability could be leveraged as an initial foothold in targeted attacks against high-value European targets, including government agencies and critical infrastructure operators.

Given the absence of an official patch, European organizations should implement layered mitigations: 1) Enforce strict email and file filtering to block or quarantine Visio files from untrusted sources. 2) Educate users about the risks of opening unsolicited or unexpected Visio documents, emphasizing caution with email attachments. 3) Employ application whitelisting and sandboxing technologies to restrict execution of untrusted code and isolate Office applications. 4) Use endpoint detection and response (EDR) solutions to monitor for suspicious behaviors indicative of exploitation attempts, such as anomalous memory operations or process injections related to Visio. 5) Disable or restrict Visio file preview features in email clients and document management systems to reduce automatic exposure. 6) Maintain up-to-date backups and incident response plans to quickly recover from potential compromises. 7) Monitor Microsoft security advisories closely and prepare for rapid deployment of patches once available. 8) Consider upgrading to supported versions of Microsoft Office that may have mitigations or patches for this vulnerability.