CVE-2025-8302 is a high-severity heap-based buffer overflow vulnerability found in the Realtek rtl81xx SDK Wi-Fi driver, specifically within the function N6CSet_DOT11_CIPHER_DEFAULT_KEY. This flaw 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 code with low privileges on the affected system can exploit this vulnerability to overflow the heap buffer, leading to local privilege escalation. Successful exploitation allows the attacker to execute arbitrary code with SYSTEM-level privileges, effectively gaining 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, indicating high severity. The attack vector is local (AV:L), requiring low attack complexity (AC:L) and low privileges (PR:L), but no user interaction (UI:N). The scope is changed (S:C), meaning the vulnerability affects resources beyond the initially compromised component. Confidentiality, integrity, and availability impacts are all high. The affected product version is rtl81xx SDK 1030.38.712.2019. No public exploits are known at this time, and no patches have been linked yet. This vulnerability was assigned by ZDI (Zero Day Initiative) under ZDI-CAN-26553 and was published in September 2025.

For European organizations, this vulnerability poses a significant risk, especially in environments where Realtek rtl81xx SDK Wi-Fi drivers are deployed. Since exploitation requires local code execution, the initial compromise vector might be through phishing, malware, or other local attack methods. Once exploited, attackers can escalate privileges to SYSTEM level, potentially leading to full system compromise, data theft, disruption of services, or lateral movement within corporate networks. This is particularly critical for sectors with sensitive data such as finance, healthcare, government, and critical infrastructure. The ability to execute arbitrary code with SYSTEM privileges can undermine endpoint security controls and facilitate persistent threats. Given the widespread use of Realtek Wi-Fi chipsets in laptops, desktops, and embedded devices, the vulnerability could affect a broad range of endpoints. The lack of a patch at the time of disclosure increases the window of exposure, necessitating immediate mitigation efforts. Additionally, the change in scope means that the impact can extend beyond the initially compromised driver, potentially affecting other system components and services.

1. Immediate mitigation should focus on minimizing the risk of initial low-privileged code execution. This includes enforcing strict application whitelisting, endpoint detection and response (EDR) solutions, and user privilege management to reduce the attack surface. 2. Network segmentation and isolation of critical systems can limit lateral movement if exploitation occurs. 3. Monitor systems for unusual behavior indicative of privilege escalation attempts, such as unexpected SYSTEM-level process creation or memory anomalies. 4. Since no official patch is available yet, consider deploying host-based intrusion prevention systems (HIPS) with rules targeting heap overflow patterns or suspicious calls to the vulnerable function if feasible. 5. Coordinate with Realtek and device vendors for timely updates and patches; prioritize patch deployment once available. 6. Conduct thorough inventory and asset management to identify all devices running the affected rtl81xx SDK version. 7. Educate users on phishing and malware risks to reduce the likelihood of initial low-privilege code execution. 8. For environments where patching is delayed, consider temporary disabling or restricting the use of affected Wi-Fi drivers if operationally possible.