CVE-2025-5318 is an out-of-bounds read vulnerability discovered in the libssh library, specifically in versions before 0.11.2. The flaw exists in the sftp_handle function, where an incorrect comparison check fails to properly validate the index or pointer against the bounds of the handle list. This allows the function to access memory locations beyond the allocated array, returning an invalid pointer. Subsequent processing of this pointer can lead to reading unintended memory regions, potentially exposing sensitive data such as cryptographic keys, credentials, or other confidential information stored in memory. The vulnerability requires an attacker to be authenticated, meaning they must have valid credentials to interact with the SSH server. However, no user interaction is needed beyond authentication, and the attack can be performed remotely over the network. The vulnerability affects Red Hat Enterprise Linux 10, which bundles libssh versions prior to 0.11.2. Although no public exploits have been reported, the medium CVSS score of 5.4 reflects the moderate risk posed by this vulnerability due to its potential to leak sensitive information and affect the integrity of the service. The flaw does not directly impact availability, and exploitation complexity is low given the network attack vector and low attack complexity. The vulnerability was published on June 24, 2025, and no patches or exploit mitigations were linked in the provided data, indicating the need for immediate vendor updates or workarounds once available.

For European organizations, this vulnerability poses a risk primarily to confidentiality and integrity of sensitive data handled by SSH and SFTP services using vulnerable libssh versions. Organizations relying on Red Hat Enterprise Linux 10 for critical infrastructure, secure file transfers, or remote administration could have sensitive memory contents exposed to authenticated attackers, potentially leading to data breaches or unauthorized information disclosure. While availability is not directly impacted, the integrity of the service could be compromised if attackers manipulate the invalid pointers or cause unexpected behavior. The requirement for authentication limits the attack surface to insiders or compromised accounts, but given the widespread use of SSH for remote access and automation, the risk remains significant. European sectors such as finance, government, energy, and telecommunications, which heavily depend on secure remote access, could face operational and reputational damage if exploited. The absence of known exploits reduces immediate threat but does not eliminate the risk of future exploitation. Organizations must assess their exposure based on their use of affected libssh versions and the criticality of the data processed.

European organizations should immediately inventory their systems to identify deployments of libssh versions earlier than 0.11.2, especially within Red Hat Enterprise Linux 10 environments. Applying vendor patches or updates as soon as they become available is the most effective mitigation. In the interim, organizations should restrict SSH and SFTP access to trusted users and networks, enforce strong authentication mechanisms such as multi-factor authentication to reduce the risk of compromised credentials, and monitor SSH logs for unusual or unauthorized access attempts. Network segmentation can limit exposure of vulnerable services to internal or less trusted networks. Additionally, consider deploying host-based intrusion detection systems (HIDS) to detect anomalous behavior related to SSH sessions. If patching is delayed, disabling or limiting SFTP functionality where feasible can reduce the attack surface. Regularly updating and auditing SSH configurations to follow best security practices will also help mitigate exploitation risks. Finally, maintain awareness of vendor advisories for patches or workarounds and test updates in controlled environments before deployment.