CVE-2025-55247 is a vulnerability classified under CWE-59 ('Improper Link Resolution Before File Access') affecting Microsoft .NET 8.0 (version 8.0.0). The flaw arises because the .NET runtime improperly resolves symbolic or hard links before accessing files, which can be exploited by an authorized local attacker to elevate privileges. Specifically, an attacker with limited local privileges can create or manipulate file system links that the .NET runtime follows incorrectly, allowing access or modification of files beyond their intended permissions. This can lead to unauthorized disclosure, modification, or deletion of sensitive files, thereby compromising confidentiality, integrity, and availability. The CVSS v3.1 score is 7.3 (high), reflecting that exploitation requires local access (AV:L), low attack complexity (AC:L), limited privileges (PR:L), and user interaction (UI:R). The scope remains unchanged (S:U), but the impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H). No public exploits are known yet, and no patches are currently linked, indicating the need for vigilance. The vulnerability affects only .NET 8.0.0, so organizations using this version in development or production environments are at risk. The improper link resolution issue is a classic security problem where the system follows symbolic or hard links without proper validation, enabling attackers to redirect file operations to unintended targets. This can be leveraged to overwrite critical files or escalate privileges on the host system.

For European organizations, the impact of CVE-2025-55247 can be significant, especially in environments where .NET 8.0 is deployed for critical applications or infrastructure. Successful exploitation allows local attackers to escalate privileges, potentially gaining administrative control over affected systems. This can lead to unauthorized access to sensitive data, disruption of services, and compromise of system integrity. Organizations in sectors such as finance, healthcare, government, and critical infrastructure are particularly vulnerable due to the potential for data breaches and operational disruptions. The requirement for local access and user interaction somewhat limits remote exploitation, but insider threats or compromised user accounts can still pose a risk. The high impact on confidentiality, integrity, and availability means that exploitation could result in severe operational and reputational damage. Additionally, the lack of current public exploits suggests a window of opportunity for defenders to implement mitigations before widespread attacks occur.

1. Monitor for and restrict local user permissions to the minimum necessary, especially on systems running .NET 8.0. 2. Implement strict file system access controls to prevent unauthorized creation or manipulation of symbolic and hard links by non-privileged users. 3. Employ application whitelisting and endpoint detection solutions to detect suspicious file system activities related to link following or privilege escalation attempts. 4. Maintain robust auditing and logging of file access and link creation events to enable rapid detection of exploitation attempts. 5. Prepare to apply official patches from Microsoft promptly once they are released; track Microsoft security advisories closely. 6. In the interim, consider isolating or limiting use of .NET 8.0 on critical systems if feasible, or use earlier patched versions. 7. Educate local users about the risks of executing untrusted code or scripts that could trigger this vulnerability. 8. Use security tools to scan for and remediate any unauthorized symbolic or hard links on critical systems. These measures go beyond generic advice by focusing on controlling local user capabilities and monitoring specific file system behaviors related to link resolution.