CVE-2025-14831 is a vulnerability identified in the GnuTLS library as used in Red Hat Enterprise Linux 10. The flaw stems from inefficient algorithmic complexity when parsing X.509 certificates that contain a large number of name constraints and subject alternative names (SANs). Specifically, the certificate validation process consumes excessive CPU and memory resources when handling these specially crafted certificates. This resource exhaustion can be triggered remotely without authentication or user interaction by an attacker sending malicious certificates during TLS handshakes or other certificate validation processes. The vulnerability leads to a denial of service (DoS) condition by overwhelming the system’s processing capabilities, potentially causing service outages or degraded performance. The CVSS v3.1 base score is 5.3, reflecting a medium severity level due to the lack of impact on confidentiality or integrity and the absence of required privileges or user interaction. No known exploits have been reported in the wild to date. The vulnerability highlights the risks associated with algorithmic complexity attacks where the computational cost of processing input data grows disproportionately with crafted inputs. Red Hat Enterprise Linux 10 users should be aware of this issue, especially those operating public-facing services that validate certificates from untrusted sources.

The primary impact of CVE-2025-14831 is denial of service through resource exhaustion, which can disrupt availability of services relying on GnuTLS for certificate validation. Organizations running Red Hat Enterprise Linux 10 in environments where TLS certificates are processed from external or untrusted sources are at risk of having their systems overwhelmed by maliciously crafted certificates. This can lead to service outages, degraded performance, and potential cascading failures in dependent systems. While confidentiality and integrity remain unaffected, the availability impact can be significant for critical infrastructure, web servers, VPN gateways, and other security-sensitive applications. The medium CVSS score reflects the moderate risk, but the ease of remote exploitation without authentication increases the threat level. The absence of known exploits suggests limited current exploitation, but the vulnerability could be leveraged in targeted attacks or as part of larger denial of service campaigns. Organizations with high volumes of TLS traffic or complex certificate validation requirements may experience amplified effects.

To mitigate CVE-2025-14831, organizations should apply patches or updates from Red Hat as soon as they become available to address the inefficient certificate parsing in GnuTLS. In the interim, administrators can implement controls to limit the complexity of certificates accepted, such as restricting the number of name constraints and SAN entries allowed by policy or filtering certificates before validation. Network-level protections like rate limiting TLS handshake attempts and deploying Web Application Firewalls (WAFs) or Intrusion Prevention Systems (IPS) with signatures to detect anomalous certificate patterns can reduce exposure. Monitoring system resource usage and TLS handshake failures can help identify attempted exploitation. Additionally, isolating critical services and employing resource quotas or containerization can limit the impact of potential DoS conditions. Regularly reviewing and updating TLS configurations to use robust and well-maintained libraries will also reduce risk. Finally, educating security teams about algorithmic complexity attacks can improve incident response readiness.