CVE-2025-5318 is an out-of-bounds read vulnerability identified in the libssh library versions earlier than 0.11.2, specifically impacting the sftp_handle function. The root cause is an incorrect comparison check that fails to properly validate the index or pointer against the valid handle list boundaries. This flaw allows the function to access memory beyond the allocated handle list, returning an invalid pointer that is subsequently used in further processing. Because the vulnerability is triggered during SFTP operations, an authenticated remote attacker with valid credentials can exploit this to read unintended memory regions. The exposed memory may contain sensitive information, such as cryptographic keys, user data, or internal state information, which could lead to information disclosure. Although the vulnerability does not directly allow code execution or modification of data, the confidentiality impact is high. The vulnerability requires authentication but no user interaction, and the attack vector is network-based, making it remotely exploitable. The CVSS 3.1 score of 7.1 reflects these factors: network attack vector, low attack complexity, privileges required, no user interaction, and high confidentiality impact with limited integrity and availability impact. The vulnerability affects Red Hat Enterprise Linux 10, which bundles libssh versions prior to 0.11.2. No public exploits have been reported so far, but the presence of the vulnerability in a widely used SSH library and operating system makes it a significant concern for organizations relying on secure file transfer and SSH communications.

For European organizations, the primary impact of CVE-2025-5318 is the potential exposure of sensitive information through unintended memory reads during SFTP sessions. This could compromise confidentiality of critical data, including credentials, encryption keys, or proprietary information. Organizations in sectors such as finance, government, healthcare, and critical infrastructure that rely heavily on secure SSH communications and file transfers are particularly at risk. The vulnerability could also lead to service instability or crashes if the invalid pointer usage causes memory faults, affecting availability. Given that exploitation requires authentication, insider threats or compromised credentials could be leveraged to exploit this vulnerability. The impact is heightened in environments where libssh is used extensively for automated or high-volume SFTP operations. Failure to patch could lead to data breaches or lateral movement within networks. The lack of known exploits in the wild currently reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits over time.

European organizations should immediately verify the versions of libssh deployed within their environments, particularly on Red Hat Enterprise Linux 10 systems. The primary mitigation is to upgrade libssh to version 0.11.2 or later, where the vulnerability is fixed. If immediate upgrade is not feasible, organizations should restrict access to SFTP services to trusted users and networks, enforce strong authentication mechanisms, and monitor for unusual SFTP activity that could indicate exploitation attempts. Implementing network segmentation and limiting SSH/SFTP access to essential personnel reduces the attack surface. Additionally, auditing and rotating credentials regularly can mitigate risks from compromised accounts. Organizations should also apply any vendor-provided patches or security advisories promptly. Employing runtime protections such as memory access monitoring or intrusion detection systems tuned for SSH anomalies can provide additional defense layers. Finally, maintaining up-to-date threat intelligence and monitoring for emerging exploits related to CVE-2025-5318 is recommended.