CVE-2025-47987 is a heap-based buffer overflow vulnerability identified in the Windows Credential Security Support Provider (CredSSP) protocol implementation on Microsoft Windows 10 Version 1809 (build 10.0.17763.0). This vulnerability arises due to improper handling of memory buffers on the heap, which can be exploited by an authorized local attacker to execute arbitrary code with elevated privileges. Specifically, the flaw allows an attacker who already has limited access to the system to overflow a heap buffer, potentially overwriting critical memory structures. This can lead to full privilege escalation, granting the attacker SYSTEM-level rights. The vulnerability does not require user interaction but does require the attacker to have some level of local access (low privileges). The CVSS v3.1 score of 7.8 (high severity) reflects the significant impact on confidentiality, integrity, and availability, as successful exploitation can compromise the entire system. No known exploits are currently reported in the wild, and no official patches or mitigations have been linked yet. The vulnerability is classified under CWE-122 (Heap-based Buffer Overflow), a common and dangerous class of memory corruption bugs that often lead to code execution or system compromise. Given the affected product is Windows 10 Version 1809, which is an older but still in-use version of Windows, systems running this version are at risk if unpatched.

For European organizations, this vulnerability poses a serious risk, especially in environments where Windows 10 Version 1809 remains in use. The ability for a local attacker to escalate privileges can lead to full system compromise, enabling lateral movement, data exfiltration, and disruption of critical services. This is particularly concerning for sectors with sensitive data such as finance, healthcare, government, and critical infrastructure, where elevated privileges can undermine security controls and lead to severe breaches. Since the vulnerability affects the CredSSP protocol, which is involved in authentication processes, exploitation could also impact remote desktop services and other authentication-dependent applications, increasing the attack surface. The lack of known exploits in the wild suggests a window of opportunity for defenders to patch and mitigate before widespread exploitation occurs. However, organizations with legacy systems or delayed patch management practices are at heightened risk. The impact extends beyond confidentiality to integrity and availability, as attackers gaining SYSTEM privileges can install persistent malware, disrupt operations, or destroy data.

European organizations should prioritize the following specific mitigation steps: 1) Identify and inventory all systems running Windows 10 Version 1809 to assess exposure. 2) Apply any available security updates from Microsoft immediately once released; monitor official Microsoft security advisories closely. 3) If patches are not yet available, consider temporary mitigations such as restricting local user access to trusted personnel only, enforcing strict access controls, and disabling unnecessary services that rely on CredSSP. 4) Employ application whitelisting and endpoint detection and response (EDR) solutions to detect anomalous privilege escalation attempts. 5) Conduct thorough audits of local user accounts and remove or disable unnecessary accounts to reduce the attack surface. 6) Implement network segmentation to limit the spread of potential compromises. 7) Educate IT staff about the vulnerability and signs of exploitation to enable rapid response. 8) Plan for an upgrade path to a supported and patched Windows version, as Windows 10 Version 1809 is an older release with limited support lifecycle remaining. These targeted actions go beyond generic advice by focusing on the specific affected version, local privilege requirements, and the nature of the CredSSP protocol.