CVE-2025-8302 is a high-severity heap-based buffer overflow vulnerability identified in the Realtek rtl81xx SDK Wi-Fi driver, specifically within the function N6CSet_DOT11_CIPHER_DEFAULT_KEY. This vulnerability arises due to improper validation of the length of user-supplied data before copying it into a fixed-length heap buffer. An attacker who already has the ability to execute low-privileged code on a system with the affected Realtek rtl81xx SDK version 1030.38.712.2019 can exploit this flaw to perform a local privilege escalation. By overflowing the heap buffer, the attacker can overwrite critical memory structures, enabling arbitrary code execution with SYSTEM-level privileges. This effectively allows the attacker to gain full control over the affected system. The vulnerability is classified under CWE-122 (Heap-based Buffer Overflow) and has a CVSS v3.0 base score of 8.8, reflecting its high impact on confidentiality, integrity, and availability. Exploitation requires local access and low privileges but does not require user interaction. No public exploits are currently known in the wild, and no patches have been linked yet. The vulnerability was reserved on July 28, 2025, and published on September 2, 2025, with assignment by the Zero Day Initiative (ZDI).

For European organizations, this vulnerability poses a significant risk, especially in environments where Realtek rtl81xx SDK Wi-Fi drivers are deployed on endpoint devices, embedded systems, or network appliances. Successful exploitation can lead to full system compromise, allowing attackers to bypass security controls, access sensitive data, disrupt services, or use compromised systems as footholds for lateral movement within corporate networks. Given the widespread use of Realtek network components in consumer and enterprise devices, organizations in sectors such as finance, healthcare, government, and critical infrastructure could face severe operational and reputational damage. The local nature of the exploit means that initial compromise vectors (e.g., phishing, malware) could be leveraged to escalate privileges rapidly. The confidentiality, integrity, and availability of affected systems are all at high risk, potentially leading to data breaches, service outages, and compliance violations under regulations like GDPR.

Organizations should immediately inventory their devices to identify those running the affected Realtek rtl81xx SDK version 1030.38.712.2019. Since no official patches are currently linked, organizations should monitor Realtek and vendor advisories closely for updates or patches. In the interim, implement strict access controls to limit local user privileges and prevent untrusted code execution. Employ application whitelisting and endpoint detection and response (EDR) solutions to detect anomalous behavior indicative of exploitation attempts. Network segmentation can reduce the risk of lateral movement if a device is compromised. Additionally, enforce strong user authentication and minimize the number of users with local execution rights. Regularly update and patch all software components, and consider deploying intrusion prevention systems (IPS) with signatures targeting heap overflow exploitation techniques. Finally, conduct user awareness training to reduce the likelihood of initial low-privilege code execution vectors such as phishing.