CVE-2025-29964 is a high-severity heap-based buffer overflow vulnerability identified in the Windows Media component of Microsoft Windows 10 Version 1809 (build 10.0.17763.0). This vulnerability arises from improper handling of memory buffers in the Windows Media processing code, which can be exploited by an unauthorized attacker to execute arbitrary code remotely over a network. Specifically, the flaw allows an attacker to send specially crafted media data that triggers a heap overflow, corrupting memory and enabling code execution in the context of the affected system. The vulnerability does not require any privileges (PR:N) but does require user interaction (UI:R), such as opening a malicious media file or streaming malicious media content. The CVSS v3.1 base score is 8.8, reflecting high impact on confidentiality, integrity, and availability (all rated high), with low attack complexity and no privileges required. Although no known exploits are currently observed in the wild, the vulnerability's characteristics make it a significant threat, especially given the widespread use of Windows 10 Version 1809 in enterprise environments. The lack of an available patch at the time of publication increases the urgency for mitigation and monitoring. This vulnerability falls under CWE-122 (Heap-based Buffer Overflow), a common and dangerous class of memory corruption bugs that can lead to remote code execution and system compromise.

For European organizations, the impact of CVE-2025-29964 could be substantial. Many enterprises and public sector entities still operate legacy systems running Windows 10 Version 1809 due to compatibility and operational constraints. Exploitation could lead to full system compromise, data breaches, ransomware deployment, or disruption of critical services. Confidentiality is at high risk as attackers could exfiltrate sensitive data; integrity is compromised through potential unauthorized code execution; and availability could be affected by system crashes or denial-of-service conditions. The network-based attack vector means that attackers can exploit this vulnerability remotely, increasing the risk of widespread attacks within corporate networks or across internet-facing systems. The requirement for user interaction (e.g., opening a malicious media file) means that social engineering or phishing campaigns could be leveraged to trigger exploitation. Given the high severity and potential for lateral movement post-compromise, European organizations in sectors such as finance, healthcare, government, and critical infrastructure could face significant operational and reputational damage if targeted.

Given the absence of an official patch at the time of disclosure, European organizations should implement immediate compensating controls. These include: 1) Restricting or disabling Windows Media playback capabilities on systems running Windows 10 Version 1809, especially on endpoints exposed to untrusted media content; 2) Employing network-level protections such as intrusion prevention systems (IPS) with signatures or heuristics to detect and block suspicious media streams or malformed packets targeting Windows Media; 3) Enhancing email and web filtering to block or quarantine potentially malicious media files; 4) Educating users to avoid opening unsolicited or suspicious media files and to report phishing attempts; 5) Applying strict application whitelisting and endpoint detection and response (EDR) solutions to detect anomalous behaviors indicative of exploitation attempts; 6) Prioritizing upgrade or migration plans to newer, supported Windows versions where this vulnerability is not present or patched; 7) Monitoring security advisories from Microsoft and CISA for the release of official patches and applying them promptly once available.