CVE-2026-25166 is a vulnerability classified under CWE-502 (Deserialization of Untrusted Data) affecting Microsoft Windows 10 Version 1607 (build 10.0.14393.0). The issue resides in the Windows System Image Manager component, which improperly handles deserialization of data that can be controlled by an attacker with authorized local access. Deserialization vulnerabilities occur when untrusted input is deserialized without adequate validation, allowing attackers to manipulate the process to execute arbitrary code. In this case, an attacker with local privileges can craft malicious serialized data that, when processed by the System Image Manager, leads to remote code execution on the affected system. The vulnerability does not require user interaction, increasing its risk profile. The CVSS v3.1 base score of 7.8 indicates high severity, with attack vector local (AV:L), low attack complexity (AC:L), privileges required (PR:L), no user interaction (UI:N), and high impact on confidentiality, integrity, and availability (C:H/I:H/A:H). Although no known exploits have been reported in the wild, the vulnerability poses a significant threat to systems still running this legacy Windows version, which is no longer widely supported. The lack of available patches at the time of publication further elevates the risk for affected environments.

The vulnerability allows an attacker with local authorized access to execute arbitrary code with potentially elevated privileges, compromising system confidentiality, integrity, and availability. This could lead to unauthorized data access, modification, or deletion, installation of persistent malware, and disruption of critical system functions. Since the affected Windows 10 Version 1607 is an older release, many organizations may still have legacy systems in place, especially in industrial, governmental, or specialized enterprise environments. Exploitation could facilitate lateral movement within networks, privilege escalation, and establishment of footholds for further attacks. The absence of user interaction lowers the barrier for exploitation once local access is obtained, increasing the likelihood of successful attacks in environments where local access controls are weak or compromised. The overall impact is high, potentially leading to significant operational disruption and data breaches.

1. Upgrade affected systems to a supported and fully patched version of Windows 10 or later, as Windows 10 Version 1607 is outdated and likely out of mainstream support. 2. Restrict local access to trusted users only, implementing strict access controls and monitoring for unauthorized local logins. 3. Employ application whitelisting and endpoint protection solutions that can detect and block suspicious deserialization activities or unauthorized code execution attempts. 4. Use system hardening techniques to minimize attack surface, such as disabling or restricting the use of Windows System Image Manager where not needed. 5. Monitor system logs and security events for anomalies related to deserialization or unexpected process executions. 6. Implement network segmentation to limit the impact of compromised local accounts. 7. Stay informed on vendor advisories for patches or workarounds and apply them promptly once available. 8. Conduct regular security assessments and penetration testing focusing on legacy systems to identify and remediate similar vulnerabilities.