CVE-2025-24057 is a heap-based buffer overflow vulnerability identified in Microsoft Office 2019 (version 19.0.0). This vulnerability arises from improper handling of heap memory during document processing, which can be triggered when a user opens a specially crafted Office document. The flaw allows an attacker to overwrite heap memory, potentially leading to arbitrary code execution with the privileges of the current user. Notably, the vulnerability requires local access and user interaction (opening a malicious document), but no prior authentication or elevated privileges are necessary. The CVSS 3.1 score of 7.8 reflects a high severity due to the combination of local attack vector, low attack complexity, no privileges required, and user interaction needed. The impact includes full compromise of confidentiality, integrity, and availability of the affected system. Although no public exploits have been reported yet, the vulnerability's nature makes it a significant risk, especially in environments where users frequently handle Office documents from untrusted sources. The vulnerability is classified under CWE-122 (Heap-based Buffer Overflow), a common and dangerous class of memory corruption bugs that can lead to code execution or system crashes. The lack of an available patch at the time of publication necessitates immediate mitigation efforts to reduce exposure.

For European organizations, the impact of CVE-2025-24057 is substantial. Microsoft Office is widely used across enterprises, government agencies, and critical infrastructure sectors throughout Europe. Successful exploitation can lead to local code execution, enabling attackers to install malware, steal sensitive data, or disrupt operations. This is particularly concerning for sectors reliant on document workflows, such as finance, legal, healthcare, and public administration. The vulnerability's requirement for user interaction means phishing or social engineering campaigns could be leveraged to deliver malicious documents. Given the high confidentiality, integrity, and availability impact, exploitation could result in data breaches, ransomware deployment, or operational downtime. The absence of known exploits currently provides a window for proactive defense, but the high severity score indicates that attackers may develop exploits rapidly once the vulnerability becomes widely known.

1. Monitor for official patches from Microsoft and apply them immediately upon release to remediate the vulnerability. 2. Until patches are available, implement strict application control policies to restrict execution of untrusted Office macros and scripts. 3. Employ email filtering and advanced threat protection to block or quarantine suspicious Office documents from unknown or untrusted sources. 4. Educate users on the risks of opening unsolicited or unexpected Office documents, emphasizing caution with email attachments. 5. Use endpoint detection and response (EDR) solutions to monitor for anomalous behaviors indicative of exploitation attempts. 6. Consider disabling or limiting legacy Office features that process complex document content if not required. 7. Enforce the principle of least privilege to minimize the impact of local code execution by restricting user permissions. 8. Regularly back up critical data and verify backup integrity to enable recovery in case of compromise. These measures collectively reduce the attack surface and improve resilience against exploitation of this vulnerability.