CVE-2025-59295 is a heap-based buffer overflow vulnerability classified under CWE-122, affecting Internet Explorer running on Microsoft Windows 11 Version 25H2 (build 10.0.26200.0). The flaw arises from improper handling of heap memory during certain operations within Internet Explorer, which can be triggered remotely by an attacker over the network. Exploiting this vulnerability allows an attacker to execute arbitrary code with the privileges of the current user, potentially leading to full system compromise. The attack vector requires no prior authentication but does require user interaction, such as visiting a malicious website or opening a crafted document that triggers the vulnerability. The CVSS v3.1 base score is 8.8, reflecting high impact on confidentiality, integrity, and availability, with low attack complexity and no privileges required. Although no known exploits are currently reported in the wild, the vulnerability's nature and severity make it a prime candidate for future exploitation. The lack of available patches at the time of publication increases the urgency for organizations to implement interim mitigations. Internet Explorer, while deprecated, remains present in Windows 11 for legacy compatibility, which broadens the attack surface. The vulnerability's exploitation could allow attackers to install malware, steal sensitive data, or disrupt services, posing significant risks to affected systems.

For European organizations, this vulnerability poses a significant risk due to the widespread use of Windows 11 in corporate and government environments. Successful exploitation can lead to unauthorized remote code execution, enabling attackers to gain control over affected systems, steal confidential information, disrupt operations, or deploy ransomware. Critical infrastructure sectors such as finance, healthcare, energy, and public administration are particularly vulnerable due to their reliance on Windows-based systems and the potential impact of service disruption. The requirement for user interaction means phishing or social engineering campaigns could be leveraged to trigger the exploit, increasing the risk to organizations with less mature security awareness programs. The high CVSS score indicates a severe threat that could compromise data confidentiality, system integrity, and availability simultaneously. The absence of patches at the time of disclosure means organizations must rely on alternative mitigations to reduce exposure. Additionally, the presence of Internet Explorer components in Windows 11, despite its deprecated status, means legacy applications and workflows may inadvertently expose organizations to this risk.

1. Disable Internet Explorer components where possible, or restrict its use through Group Policy to prevent access to untrusted websites. 2. Employ application whitelisting to block unauthorized execution of Internet Explorer or related processes. 3. Use network-level protections such as web proxies and intrusion prevention systems to detect and block malicious traffic targeting Internet Explorer vulnerabilities. 4. Increase user awareness and training to recognize phishing attempts and avoid interacting with suspicious links or documents. 5. Monitor endpoint and network logs for unusual activity indicative of exploitation attempts, including unexpected Internet Explorer processes or network connections. 6. Prepare for rapid deployment of official patches once released by Microsoft, including testing and validation in controlled environments. 7. Consider isolating legacy applications requiring Internet Explorer in sandboxed or virtualized environments to limit potential damage. 8. Review and update incident response plans to address potential exploitation scenarios involving this vulnerability. 9. Maintain up-to-date backups to enable recovery in case of compromise. 10. Collaborate with cybersecurity information sharing groups to stay informed about emerging exploit techniques related to this vulnerability.