CVE-2026-20832 is a vulnerability identified in Microsoft Windows 10 Version 1607 (build 10.0.14393.0) involving a double free condition in the Windows Remote Procedure Call (RPC) Interface Definition Language (IDL) component. The double free vulnerability (CWE-415) occurs when the system attempts to free the same memory location twice, which can lead to memory corruption. This corruption can be exploited by an attacker with low privileges and local access to escalate their privileges to SYSTEM level, effectively gaining full control over the affected machine. The vulnerability does not require user interaction and has a low attack complexity, making exploitation feasible in targeted scenarios. The CVSS v3.1 base score of 7.8 reflects high severity, with impacts on confidentiality, integrity, and availability (all rated high). The attack vector is local (AV:L), requiring the attacker to have some level of access to the system, but no authentication beyond low privileges is needed (PR:L). The vulnerability is currently published but has no known exploits in the wild, and no official patches have been linked yet, indicating that mitigation relies on defensive measures and monitoring until a patch is released. The flaw resides in a core Windows component used for inter-process communication, making it a critical issue for systems still running this legacy version of Windows 10.

The vulnerability allows an attacker with limited local privileges to escalate to SYSTEM-level privileges, potentially leading to full system compromise. This can result in unauthorized access to sensitive data, modification or deletion of critical system files, and disruption of system availability. Organizations relying on Windows 10 Version 1607, especially those with legacy systems in production environments, face increased risk of insider threats or malware leveraging this flaw to gain persistent elevated access. The lack of user interaction requirement and low complexity of exploitation increase the likelihood of successful attacks in environments where local access is possible. This could impact enterprise networks, government agencies, and critical infrastructure sectors that have not upgraded from this Windows version. The absence of known exploits in the wild currently limits immediate widespread impact, but the vulnerability remains a significant risk if weaponized by attackers.

1. Restrict local access to systems running Windows 10 Version 1607 by enforcing strict access controls and limiting administrative privileges. 2. Monitor RPC-related processes and system logs for unusual activity indicative of exploitation attempts, such as unexpected memory errors or crashes. 3. Implement application whitelisting and endpoint detection and response (EDR) solutions to detect and block suspicious behavior related to privilege escalation. 4. Plan and execute an upgrade strategy to move affected systems off Windows 10 Version 1607 to supported versions with active security updates. 5. Apply any security patches or updates from Microsoft as soon as they become available for this vulnerability. 6. Conduct regular security audits and vulnerability assessments focusing on legacy systems to identify and remediate similar risks. 7. Educate local users about the risks of executing untrusted code or scripts that could exploit local vulnerabilities.