CVE-2024-12747 is a race condition vulnerability discovered in the widely used file synchronization tool rsync. The flaw arises from improper synchronization when rsync encounters symbolic links during its operation. By default, rsync skips symbolic links to avoid unintended traversal. However, an attacker with local access can exploit a timing window by replacing a regular file with a symbolic link at the precise moment rsync processes the file. This race condition allows rsync to traverse symbolic links unexpectedly, potentially exposing sensitive files or directories that should have been skipped. The impact depends on the privileges under which the rsync process runs; if it runs with elevated privileges, this can lead to information disclosure and possibly privilege escalation. The CVSS v3.1 score is 5.6 (medium severity), reflecting a local attack vector, high attack complexity, low privileges required, no user interaction, and a scope change due to the potential for privilege escalation. No public exploits have been reported yet, but the vulnerability is significant for environments relying on rsync for secure file transfers, especially in multi-user or shared environments. The vulnerability was reserved in December 2024 and published in January 2025, with no patch links currently provided, indicating that remediation may still be pending or in progress.

For European organizations, the vulnerability poses a risk primarily to systems where rsync is used for file synchronization, backup, or deployment tasks, particularly when rsync runs with elevated privileges or in multi-tenant environments. Exploitation could lead to unauthorized disclosure of sensitive information, such as configuration files, credentials, or proprietary data, undermining confidentiality. In some cases, privilege escalation could allow attackers to gain higher system privileges, threatening system integrity and potentially enabling further compromise. This risk is heightened in sectors with stringent data protection requirements, such as finance, healthcare, and government, where data leakage or unauthorized access can have severe regulatory and operational consequences. The medium severity score suggests that while exploitation is not trivial, the impact on confidentiality is significant, warranting prompt attention. Availability is not directly impacted by this vulnerability. The lack of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits over time.

Organizations should monitor vendor advisories closely and apply official patches or updates for rsync as soon as they become available. Until patches are released, it is advisable to run rsync with the least privileges necessary, avoiding execution as root or other privileged users. Implement file system monitoring to detect unexpected symbolic link creation or replacement during synchronization operations. Consider using alternative synchronization methods or tools that do not exhibit this race condition if feasible. Employ access controls and restrict local user permissions to minimize the ability of attackers to manipulate files during rsync operations. Additionally, review and harden system configurations to limit the attack surface, such as disabling unnecessary local accounts and enforcing strict file permissions. Regularly audit rsync usage and logs to detect anomalous behavior that may indicate exploitation attempts. For critical environments, consider isolating rsync operations within containers or restricted environments to limit potential damage.