CVE-2025-64406 is classified as a CWE-787 out-of-bounds write vulnerability affecting Apache OpenOffice through version 4.1.15. This vulnerability arises when the application processes specially crafted documents containing malicious data that causes the program to write outside the bounds of allocated memory buffers. Such out-of-bounds writes can corrupt adjacent memory, leading to application crashes or unpredictable behavior. The vulnerability does not appear to allow direct code execution or privilege escalation but can cause denial of service by crashing the application. Exploitation requires an attacker to convince a user to open a malicious document, thus involving user interaction but no authentication. The vulnerability is network exploitable since the crafted document can be delivered via email or download. The Apache Software Foundation has addressed this issue in version 4.1.16, and users are strongly advised to upgrade. No public exploits or active exploitation campaigns have been reported to date. The CVSS v3.1 base score is 4.3, reflecting medium severity with network attack vector, low attack complexity, no privileges required, user interaction needed, and impact limited to availability. This vulnerability highlights the risks of processing untrusted document files in office productivity software and underscores the importance of timely patching.

For European organizations, this vulnerability primarily threatens availability by enabling denial of service through application crashes when opening malicious documents. While it does not compromise confidentiality or integrity, disruption of document processing workflows can impact business continuity, especially in sectors reliant on document handling such as government, legal, and finance. Organizations using Apache OpenOffice in their desktop environments or document management systems may face operational interruptions. The requirement for user interaction limits automated exploitation but phishing or social engineering campaigns could deliver malicious documents. The absence of known exploits reduces immediate risk but does not eliminate the threat, as attackers may develop exploits post-disclosure. The medium severity suggests moderate urgency; however, organizations with high document processing volumes or critical uptime requirements should prioritize remediation to avoid service disruption.

1. Upgrade all Apache OpenOffice installations to version 4.1.16 or later immediately to apply the official patch. 2. Implement email filtering and attachment scanning to detect and block suspicious or malformed documents that could exploit this vulnerability. 3. Educate users about the risks of opening documents from untrusted or unknown sources to reduce the likelihood of successful social engineering. 4. Employ application whitelisting and sandboxing where feasible to limit the impact of crashes or malicious documents. 5. Monitor endpoint logs for crashes or abnormal behavior in Apache OpenOffice that could indicate attempted exploitation. 6. Consider transitioning to alternative office suites with more active security maintenance if Apache OpenOffice usage is widespread and patching is delayed. 7. Maintain regular backups of critical documents and configurations to ensure rapid recovery from potential disruption.