CVE-2025-6395 is a vulnerability identified in the GnuTLS library used within Red Hat Enterprise Linux 10. The flaw arises from a NULL pointer dereference in the function _gnutls_figure_common_ciphersuite(), which processes certain settings from a template file. Specifically, when the function reads these settings, it can perform an out-of-bounds (OOB) NULL pointer write. This memory corruption can lead to a denial of service (DoS) condition by crashing the affected system. The vulnerability does not allow for confidentiality breaches or privilege escalation but impacts system availability by causing crashes. The CVSS 3.1 base score is 6.5 (medium severity), with the vector indicating network attack vector (AV:N), high attack complexity (AC:H), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), no confidentiality impact (C:N), low integrity impact (I:L), and high availability impact (A:H). No known exploits are currently reported in the wild, and no patches are linked yet. The vulnerability is specific to Red Hat Enterprise Linux 10, which integrates GnuTLS for cryptographic operations, including TLS/SSL communications. The flaw could be triggered remotely by an attacker who can influence the template file settings processed by the vulnerable function, although the high attack complexity suggests exploitation is non-trivial. The impact is primarily a denial of service through system crashes caused by memory corruption due to the NULL pointer dereference and OOB write.

For European organizations, this vulnerability poses a risk primarily to availability of systems running Red Hat Enterprise Linux 10, especially those relying on GnuTLS for secure communications. Critical infrastructure, financial institutions, and service providers using this OS version could experience service disruptions if exploited, potentially affecting business continuity and operational reliability. Since the flaw can be triggered remotely without authentication or user interaction, exposed network services using GnuTLS could be targeted to cause outages. However, the high attack complexity reduces the likelihood of widespread exploitation. The absence of confidentiality impact limits risks related to data breaches. Organizations with strict uptime requirements or those operating in regulated sectors (e.g., healthcare, finance) must consider the potential operational impact. The lack of known exploits in the wild currently lowers immediate risk but does not preclude future exploitation once details become public or patches are delayed.

European organizations should proactively monitor Red Hat security advisories for patches addressing CVE-2025-6395 and apply them promptly once available. In the interim, administrators should audit systems running Red Hat Enterprise Linux 10 to identify services utilizing GnuTLS and assess exposure to untrusted inputs influencing template file settings. Restricting network access to such services via firewalls or network segmentation can reduce attack surface. Employing intrusion detection systems to monitor anomalous traffic patterns targeting TLS services may help detect exploitation attempts. Additionally, organizations can consider temporarily disabling or limiting features relying on the vulnerable GnuTLS function if feasible. Regular backups and system redundancy can mitigate impact from potential DoS-induced crashes. Finally, maintaining up-to-date system inventories and vulnerability management processes will facilitate rapid response once patches are released.