Suricata, an open-source network IDS/IPS and NSM engine developed by the Open Information Security Foundation (OISF), is vulnerable to a NULL pointer dereference (CWE-476) in version 8.0.0 when processing the tls.subjectaltname keyword. Specifically, if the decoded TLS subject alternative name contains a NULL byte, Suricata attempts to dereference a NULL pointer, causing a segmentation fault and crashing the process. This vulnerability leads to a denial of service (DoS) condition, disrupting network monitoring and intrusion detection capabilities. The vulnerability is remotely exploitable without authentication or user interaction, as it can be triggered by sending specially crafted TLS traffic that includes a subject alternative name with a NULL byte. The issue was addressed in Suricata version 8.0.1. Until patching is possible, disabling Suricata rules that use the tls.subjectaltname keyword serves as a workaround to prevent triggering the fault. The CVSS v3.1 score is 7.5 (high), reflecting the network attack vector, low complexity, no privileges or user interaction required, and the impact limited to availability (denial of service). No known exploits are currently in the wild, but the vulnerability poses a significant risk to organizations relying on Suricata for real-time network security monitoring.

The primary impact of CVE-2025-59150 is denial of service caused by Suricata process crashes, which can disable or degrade network intrusion detection and prevention capabilities. For European organizations, this can lead to blind spots in network security monitoring, increasing the risk of undetected cyberattacks, data breaches, or lateral movement by threat actors. Critical infrastructure sectors such as energy, finance, telecommunications, and government agencies that depend on Suricata for network defense may experience operational disruptions and increased exposure to threats. The vulnerability's ease of exploitation and remote triggerability make it a viable attack vector for adversaries aiming to disrupt security operations. Although no confidentiality or integrity impact is directly associated, the loss of availability of Suricata monitoring can indirectly facilitate more severe attacks. Organizations with high network traffic volumes and complex TLS environments may be more susceptible to frequent crashes, exacerbating the operational impact.

1. Upgrade Suricata to version 8.0.1 or later immediately to apply the official fix for the NULL pointer dereference vulnerability. 2. Until patching is feasible, disable all Suricata rules that utilize the tls.subjectaltname keyword to prevent triggering the segmentation fault. 3. Monitor Suricata logs and system stability closely for unexpected crashes or restarts that may indicate exploitation attempts. 4. Implement network-level filtering to detect and block suspicious TLS traffic containing malformed or unusual subject alternative names, if possible. 5. Employ redundancy in network monitoring by deploying multiple IDS/IPS sensors or fallback systems to maintain visibility during potential Suricata outages. 6. Conduct regular vulnerability assessments and penetration testing focused on TLS traffic handling to identify similar weaknesses. 7. Educate security operations teams about this vulnerability and the importance of timely patching and rule management to maintain continuous network defense.