CVE-2026-22259 is a vulnerability in the Suricata network security monitoring engine related to uncontrolled resource consumption (CWE-400) and improper handling of resource limits (CWE-770). Suricata versions before 7.0.14 and between 8.0.0 and 8.0.3 contain a flaw in the DNP3 protocol parser, which processes traffic commonly used in industrial control systems. When Suricata parses specially crafted DNP3 packets, it can consume excessive amounts of memory, leading to degraded performance and potential process termination by the operating system's out-of-memory (OOM) killer. This results in a denial-of-service (DoS) condition, impacting the availability of the IDS/IPS system. The vulnerability can be exploited remotely without authentication or user interaction, making it a network-exploitable DoS vector. The issue was addressed in Suricata versions 7.0.14 and 8.0.3 by patching the parser to handle resource consumption properly. As a temporary workaround, disabling the DNP3 parser in the Suricata configuration file (suricata.yaml) can prevent exploitation, though this may reduce monitoring capabilities for DNP3 traffic. No public exploits have been reported, but the vulnerability poses a significant risk to environments relying on Suricata for network security monitoring, especially those monitoring industrial protocols.

For European organizations, this vulnerability poses a significant risk to the availability of network security monitoring systems, particularly those using Suricata to monitor industrial control systems (ICS) and critical infrastructure networks that utilize the DNP3 protocol. Disruption of Suricata due to memory exhaustion can lead to blind spots in network intrusion detection and prevention, increasing the risk of undetected attacks or operational disruptions. Critical sectors such as energy, manufacturing, transportation, and utilities in Europe often rely on ICS protocols like DNP3, making them vulnerable to targeted denial-of-service attacks exploiting this flaw. The inability of Suricata to process traffic effectively could delay incident detection and response, potentially leading to broader operational impacts. Although confidentiality and integrity are not directly affected, the loss of availability in security monitoring can indirectly increase the risk of successful cyberattacks. Organizations with regulatory obligations for critical infrastructure protection in Europe could face compliance and operational risks if this vulnerability is exploited.

European organizations should prioritize upgrading Suricata to version 7.0.14 or 8.0.3 and later to apply the official patch that addresses this vulnerability. Until upgrades can be performed, disabling the DNP3 parser in the suricata.yaml configuration file is a practical workaround to prevent exploitation, noting that this may reduce visibility into DNP3 traffic. Network administrators should monitor Suricata logs and system memory usage closely for signs of abnormal resource consumption. Implementing network segmentation to isolate ICS networks and limit exposure of Suricata instances to untrusted sources can reduce attack surface. Additionally, deploying rate limiting or traffic filtering for DNP3 traffic at network boundaries can help mitigate the risk of crafted packets reaching Suricata. Regular vulnerability scanning and configuration audits should include checks for Suricata versions and parser settings. Finally, organizations should maintain incident response readiness to quickly address potential denial-of-service events impacting IDS/IPS availability.