CVE-2025-6395 is a vulnerability identified in the GnuTLS library, a widely used open-source implementation of the TLS protocol, which provides cryptographic functions for secure communications. The flaw exists in the _gnutls_figure_common_ciphersuite() function, where a NULL pointer dereference can occur. This type of vulnerability typically leads to a denial of service (DoS) condition by causing the affected application or service to crash when processing certain TLS handshake messages or cipher suite negotiations. The vulnerability affects Red Hat Enterprise Linux 10, which bundles GnuTLS as part of its cryptographic stack. According to the CVSS v3.1 score of 6.5, the vulnerability has a network attack vector (AV:N), requires high attack complexity (AC:H), no privileges (PR:N), no user interaction (UI:N), and impacts availability (A:H) with no impact on confidentiality or integrity. The high attack complexity suggests that exploiting this flaw requires specific conditions or crafted inputs, reducing the likelihood of widespread exploitation. No known exploits are currently reported in the wild, indicating that active exploitation has not been observed. However, the potential for denial of service attacks exists, which could disrupt services relying on secure TLS communications. The absence of patches or links to fixes in the provided data suggests that remediation may still be pending or in progress. Organizations using Red Hat Enterprise Linux 10 should monitor vendor advisories closely and prepare to deploy patches promptly once available.

For European organizations, the primary impact of CVE-2025-6395 is the potential for denial of service attacks against systems using the vulnerable GnuTLS library on Red Hat Enterprise Linux 10. This could lead to temporary unavailability of critical services that rely on TLS for secure communications, such as web servers, VPN gateways, mail servers, and other networked applications. While confidentiality and integrity of data are not directly affected, service disruptions can impact business operations, customer trust, and compliance with service level agreements. Sectors such as finance, healthcare, government, and critical infrastructure that depend heavily on secure and reliable communications are particularly vulnerable to operational impacts. The high attack complexity reduces the risk of widespread exploitation, but targeted attacks against high-value systems remain a concern. Additionally, denial of service conditions could be leveraged as part of multi-stage attacks or to distract security teams. Organizations with extensive Red Hat Enterprise Linux 10 deployments should assess their exposure and prioritize mitigation to maintain service continuity.

1. Monitor Red Hat security advisories and GnuTLS project updates closely for the release of patches addressing CVE-2025-6395. 2. Apply security patches promptly once available to eliminate the NULL pointer dereference vulnerability. 3. In the interim, consider deploying network-level protections such as rate limiting and anomaly detection on TLS traffic to identify and block malformed handshake attempts that could trigger the vulnerability. 4. Conduct thorough testing of TLS-dependent applications and services to identify any abnormal crashes or instability that may indicate exploitation attempts. 5. Implement robust logging and monitoring of TLS handshake failures and application crashes to detect potential denial of service activities early. 6. Where feasible, consider temporary mitigation by disabling or restricting the use of vulnerable cipher suites or GnuTLS versions until patches are applied. 7. Educate system administrators and security teams about the vulnerability characteristics and signs of exploitation to improve incident response readiness. 8. Review and update incident response plans to include scenarios involving denial of service attacks targeting cryptographic libraries.