CVE-2025-26669 is an out-of-bounds read vulnerability classified under CWE-125, found in the Windows Routing and Remote Access Service (RRAS) component of Microsoft Windows 10 Version 1507 (build 10.0.10240.0). The vulnerability arises from improper bounds checking when RRAS processes network packets, allowing an attacker to read memory beyond the intended buffer limits. This memory disclosure can reveal sensitive information, potentially including credentials, cryptographic keys, or other critical data residing in adjacent memory. The attack vector is network-based, requiring no privileges and no prior authentication, but does require user interaction, likely in the form of triggering RRAS to process crafted packets. The CVSS v3.1 score of 8.8 reflects the high impact on confidentiality, integrity, and availability, as the attacker can cause information leakage and potentially destabilize the service. Although no public exploits have been reported yet, the vulnerability's nature and ease of exploitation make it a significant threat. RRAS is commonly used for VPN and routing services, so affected systems providing these services are at risk. The vulnerability was reserved in February 2025 and published in April 2025, with no patches currently linked, indicating a need for urgent vendor response and user mitigation.

For European organizations, this vulnerability poses a serious risk especially to those still operating legacy Windows 10 Version 1507 systems with RRAS enabled. The out-of-bounds read can lead to unauthorized disclosure of sensitive information over the network, potentially exposing internal credentials, configuration data, or other confidential information. This can facilitate further attacks such as privilege escalation, lateral movement, or targeted espionage. Critical infrastructure sectors like finance, energy, healthcare, and government that rely on RRAS for secure remote access are particularly vulnerable. The high CVSS score indicates that exploitation could also impact system integrity and availability, possibly causing service disruptions. Given the lack of patches and known exploits, organizations face a window of exposure that attackers might exploit once proof-of-concept code emerges. The threat is amplified by the fact that no authentication is required, increasing the attack surface. European entities with legacy systems or insufficient network segmentation are at elevated risk of compromise and data leakage.

Immediate mitigation steps include disabling the Routing and Remote Access Service on Windows 10 Version 1507 systems if it is not essential for business operations. Network segmentation should be enforced to limit exposure of RRAS-enabled hosts to untrusted networks. Employ strict firewall rules to restrict inbound traffic to RRAS ports only from trusted sources. Monitor network traffic for unusual or malformed packets targeting RRAS services. Since no official patches are currently available, organizations should prioritize upgrading affected systems to supported Windows versions with active security updates. Implement intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics to detect exploitation attempts once available. Conduct thorough asset inventories to identify all systems running Windows 10 Version 1507 and RRAS. Prepare incident response plans for potential exploitation scenarios. Engage with Microsoft support channels for updates on patch releases and apply them promptly upon availability.