CVE-2025-5318 is an out-of-bounds read vulnerability discovered in the libssh library versions prior to 0.11.2, specifically impacting the sftp_handle function. The flaw arises from an incorrect comparison check within this function, which permits it to access memory beyond the valid handle list. As a result, the function can return an invalid pointer that is subsequently used in further processing. This memory access violation allows an authenticated remote attacker to read unintended memory regions, potentially exposing sensitive information such as cryptographic keys, credentials, or other confidential data stored in memory. The vulnerability requires the attacker to have valid authentication credentials to the SSH server using libssh, but does not require any user interaction, making it remotely exploitable over the network. The vulnerability does not cause denial of service or code execution but can affect the confidentiality and integrity of data handled by the affected service. The CVSS v3.1 base score is 5.4 (medium severity), reflecting network attack vector, low attack complexity, required privileges, no user interaction, and limited impact on confidentiality and integrity. No public exploits have been reported yet, but the vulnerability is significant for environments relying on libssh for secure file transfer (SFTP) operations. Red Hat Enterprise Linux 10 includes affected libssh versions, making it a relevant vendor product. The flaw was reserved in late May 2025 and published in June 2025, with no patch links provided in the source data, indicating that remediation may require manual updates or vendor patches once available.

For European organizations, this vulnerability poses a risk primarily to confidentiality and integrity of data transmitted or processed via libssh-based SFTP services. Attackers with valid credentials could exploit this flaw to read sensitive memory contents, potentially gaining access to private keys, passwords, or other critical information. This could facilitate further lateral movement, privilege escalation, or data exfiltration within corporate networks. While availability is not directly impacted, the exposure of sensitive data can lead to compliance violations under GDPR and other data protection regulations, resulting in legal and financial consequences. Organizations operating critical infrastructure, financial services, government agencies, or healthcare sectors that rely on Red Hat Enterprise Linux 10 and libssh for secure communications are particularly vulnerable. The medium severity score suggests a moderate risk, but the requirement for authentication limits the attack surface to insiders or compromised accounts. Nevertheless, the potential for sensitive data leakage makes this vulnerability a concern for European entities with strict data security requirements.

To mitigate CVE-2025-5318, European organizations should prioritize upgrading libssh to version 0.11.2 or later as soon as vendor patches become available. Until patches are applied, organizations should audit and restrict SSH/SFTP access to trusted users only, enforce strong authentication mechanisms such as multi-factor authentication, and monitor for unusual access patterns or memory-related anomalies in SSH services. Network segmentation can limit exposure of vulnerable services to internal networks. Additionally, reviewing and minimizing the use of SFTP handles and ensuring proper session management can reduce the risk of exploitation. Organizations should also implement strict logging and alerting on SSH authentication and file transfer activities to detect potential exploitation attempts. Regular vulnerability scanning and penetration testing targeting libssh implementations can help identify residual risks. Finally, maintaining an incident response plan that includes memory disclosure scenarios will improve readiness in case of exploitation.