CVE-2025-26630 is a high-severity use-after-free vulnerability identified in Microsoft Office 2019, specifically affecting the Microsoft Office Access component. The vulnerability arises when the software improperly manages memory, allowing an attacker to exploit a freed memory region. This can lead to arbitrary code execution in the context of the current user. The vulnerability does not require any privileges (PR:N) but does require user interaction (UI:R), such as opening a specially crafted Office Access file. The attack vector is local (AV:L), meaning the attacker must have local access to the machine or trick the user into opening a malicious file. The vulnerability impacts confidentiality, integrity, and availability (C:H/I:H/A:H), indicating that successful exploitation could lead to full system compromise, data theft, or system disruption. The CVSS 3.1 score is 7.8, categorizing it as high severity. No known exploits are currently reported in the wild, and no official patches have been linked yet. The vulnerability is tracked as CWE-416 (Use After Free), a common memory corruption issue that can be leveraged for code execution. Given the widespread use of Microsoft Office 2019 in enterprise environments, this vulnerability poses a significant risk if exploited.

For European organizations, the impact of CVE-2025-26630 could be substantial. Microsoft Office 2019 is widely deployed across various sectors including government, finance, healthcare, and critical infrastructure within Europe. Exploitation could allow attackers to execute arbitrary code locally, potentially leading to data breaches, ransomware deployment, or lateral movement within networks. The requirement for user interaction means phishing or social engineering campaigns could be used to deliver malicious Office Access files. Confidentiality and integrity of sensitive data could be compromised, impacting compliance with GDPR and other data protection regulations. Additionally, availability could be affected if attackers disrupt business operations or deploy destructive payloads. The lack of known exploits currently provides a window for organizations to prepare and mitigate risk before active exploitation emerges.

European organizations should implement targeted mitigations beyond generic advice: 1) Restrict and monitor the use of Microsoft Office Access files, especially from untrusted sources, by enforcing strict email filtering and attachment scanning policies. 2) Educate users about the risks of opening unsolicited or unexpected Office files, emphasizing the specific threat of use-after-free vulnerabilities. 3) Employ application control and sandboxing techniques to limit the execution context of Office applications, reducing the impact of potential exploitation. 4) Use endpoint detection and response (EDR) solutions to identify suspicious behaviors indicative of exploitation attempts. 5) Regularly check for and apply Microsoft security updates as soon as patches become available, given the absence of current patches. 6) Consider disabling or limiting macros and Access database features if not required for business operations. 7) Implement network segmentation to contain potential breaches originating from compromised endpoints. These measures, combined with ongoing threat intelligence monitoring, will help reduce the risk posed by this vulnerability.