CVE-2026-20828 is a security vulnerability classified as CWE-125 (Out-of-bounds Read) found in the Windows Internet Connection Sharing (ICS) component of Microsoft Windows 10 Version 1809 (build 10.0.17763.0). The flaw allows an attacker with physical access to the affected system to read memory outside the intended buffer boundaries, potentially disclosing sensitive information stored in memory. This vulnerability does not require any privileges or user interaction, making it accessible to unauthorized individuals who can physically interact with the device. The attack vector is physical access (AV:P), which limits the scope of exploitation compared to remote vulnerabilities. The vulnerability impacts confidentiality (C:H) but does not affect integrity or availability. The CVSS 3.1 base score is 4.6, indicating medium severity. No public exploits or patches are currently available, which suggests that the vulnerability is either newly discovered or not yet widely exploited. The ICS component is often used in network sharing scenarios, including in industrial and enterprise environments, which may increase the risk in certain sectors. The vulnerability's presence in an older Windows 10 version (1809) means that systems not updated or migrated to newer versions remain vulnerable. Given the physical access requirement, the threat is more relevant in environments where device access control is weak or devices are deployed in less secure locations.

For European organizations, the primary impact of CVE-2026-20828 is the potential disclosure of sensitive information due to out-of-bounds memory reads on affected Windows 10 Version 1809 systems. This could lead to leakage of confidential data, including credentials, configuration details, or other sensitive information residing in memory. The requirement for physical access reduces the risk of remote exploitation but raises concerns for organizations with devices in publicly accessible or less secure environments, such as manufacturing plants, branch offices, or shared workspaces. Critical infrastructure sectors relying on ICS for network sharing may face increased risk if legacy systems remain unpatched or un-upgraded. The vulnerability does not affect system integrity or availability, so it is unlikely to cause service disruptions or data tampering. However, information disclosure can facilitate further attacks or unauthorized access if combined with other vulnerabilities. The lack of known exploits in the wild currently limits immediate risk, but organizations should not be complacent given the potential for future exploitation. Overall, the impact is moderate but significant in contexts where physical security is insufficient and legacy Windows 10 systems are in use.

1. Upgrade affected systems from Windows 10 Version 1809 to a supported and patched version of Windows 10 or Windows 11 to eliminate the vulnerability. 2. Implement strict physical security controls to prevent unauthorized physical access to devices, especially in sensitive or publicly accessible locations. 3. Disable Internet Connection Sharing (ICS) on devices where it is not required to reduce the attack surface. 4. Monitor and audit physical access logs and device usage to detect any unauthorized interactions. 5. Use endpoint detection and response (EDR) solutions to identify unusual memory access patterns or attempts to exploit memory vulnerabilities. 6. Apply network segmentation to isolate legacy systems and limit exposure if physical access is gained. 7. Educate staff about the risks of physical device access and enforce policies to secure devices when unattended. 8. Stay informed about official patches or updates from Microsoft and apply them promptly once available. 9. Consider hardware-based security features such as Trusted Platform Module (TPM) and secure boot to protect system integrity. 10. Conduct regular vulnerability assessments and penetration testing focusing on physical security and legacy system vulnerabilities.