CVE-2025-29956 is a buffer over-read vulnerability classified under CWE-126 that affects Microsoft Windows 10 Version 1809 (build 10.0.17763.0). This vulnerability exists within the Windows Server Message Block (SMB) protocol implementation. An authorized attacker with low privileges and requiring user interaction can exploit this flaw remotely over the network. The vulnerability allows the attacker to cause the system to read beyond the intended buffer boundaries, potentially disclosing sensitive information from memory that should not be accessible. The vulnerability does not allow modification of data or denial of service but can lead to confidentiality breaches by leaking information. The CVSS v3.1 base score is 5.4 (medium severity), reflecting the need for authentication, user interaction, and high attack complexity. No known exploits are currently reported in the wild, and no patches have been linked yet. The vulnerability is significant because SMB is widely used for file sharing and network communication in Windows environments, and an information disclosure can aid attackers in further reconnaissance or targeted attacks.

For European organizations, this vulnerability poses a moderate risk primarily to confidentiality. Since SMB is extensively used in enterprise networks for file and printer sharing, an attacker who gains authorized access and tricks a user into interaction could extract sensitive information from memory. This could include credentials, cryptographic keys, or other sensitive data, potentially facilitating lateral movement or privilege escalation in the network. Organizations in sectors with strict data protection requirements, such as finance, healthcare, and government, could face compliance and reputational risks if sensitive data is leaked. However, the requirement for authentication and user interaction limits the ease of exploitation, reducing the likelihood of widespread impact. Still, legacy systems or those not updated beyond Windows 10 Version 1809 are at risk, especially if they are exposed to untrusted networks or have weak access controls.

1. Prioritize upgrading or patching Windows 10 systems running Version 1809 to a supported and updated version where this vulnerability is fixed. 2. Restrict SMB access to trusted networks only, using network segmentation and firewall rules to limit exposure. 3. Implement strict access controls and multi-factor authentication to reduce the risk of unauthorized access. 4. Educate users to recognize and avoid suspicious interactions that could trigger exploitation attempts. 5. Monitor network traffic for unusual SMB activity and use endpoint detection tools to identify potential exploitation attempts. 6. Since no patch is currently linked, consider applying temporary mitigations such as disabling SMBv1 and enforcing SMB signing to increase security. 7. Regularly review and update incident response plans to include scenarios involving SMB-related information disclosure.