CVE-2025-59208 is an out-of-bounds read vulnerability classified under CWE-125 found in the Windows MapUrlToZone function in Microsoft Windows 11 Version 25H2 (build 10.0.26200.0). The MapUrlToZone function is responsible for determining the security zone of a given URL, which is critical for enforcing security policies related to web content. The vulnerability arises when the function improperly handles input, allowing an attacker to read memory outside the intended buffer boundaries. This out-of-bounds read can lead to unauthorized disclosure of sensitive information over a network. The vulnerability does not require any privileges but does require user interaction, such as clicking a specially crafted link or visiting a malicious website that triggers the vulnerable function. The CVSS v3.1 base score is 7.1, indicating a high severity level due to the network attack vector, low attack complexity, no privileges required, and high impact on confidentiality. Integrity impact is low, and availability is unaffected. No public exploits have been reported yet, but the vulnerability is publicly disclosed and considered exploitable. The lack of an available patch at the time of disclosure means organizations must rely on interim mitigations to reduce risk. This vulnerability could be leveraged in targeted attacks to extract sensitive information from affected systems, potentially aiding further exploitation or reconnaissance.

For European organizations, the primary impact of CVE-2025-59208 is the unauthorized disclosure of sensitive information, which could include credentials, internal URLs, or other confidential data residing in memory. This compromises confidentiality and could facilitate subsequent attacks such as phishing, lateral movement, or privilege escalation. Organizations with high network exposure or those that rely heavily on Windows 11 Version 25H2 are particularly vulnerable. The vulnerability does not affect system integrity or availability, so direct disruption or data manipulation is unlikely. However, the information disclosure could have serious consequences for compliance with GDPR and other data protection regulations, potentially leading to legal and reputational damage. The requirement for user interaction means that social engineering or phishing campaigns could be used to exploit this vulnerability. Since no known exploits are in the wild yet, proactive mitigation is critical to prevent attackers from developing and deploying exploit code.

1. Monitor Microsoft security advisories closely and apply official patches immediately upon release to remediate the vulnerability. 2. Until patches are available, restrict access to Windows 11 Version 25H2 systems from untrusted networks, especially limiting exposure to the internet. 3. Implement network-level protections such as web filtering and URL reputation services to block access to malicious or suspicious URLs that could trigger the vulnerability. 4. Educate users about the risks of clicking unknown or suspicious links to reduce the likelihood of user interaction exploitation. 5. Employ endpoint detection and response (EDR) solutions to monitor for unusual behavior related to URL zone mapping or memory access anomalies. 6. Conduct regular vulnerability scanning and penetration testing focused on Windows 11 systems to identify potential exploitation attempts. 7. Use application whitelisting and restrict execution privileges to minimize the attack surface. 8. Review and tighten group policies related to URL zone security settings to limit exposure to risky zones. 9. Maintain comprehensive logging and alerting to detect early signs of exploitation attempts involving the MapUrlToZone function.