CVE-2025-59149 is a stack-based buffer overflow vulnerability identified in Suricata, an open-source network intrusion detection system (IDS), intrusion prevention system (IPS), and network security monitoring (NSM) engine developed by the Open Information Security Foundation (OISF). The vulnerability specifically affects Suricata version 8.0.0 and occurs when rules using the keyword ldap.responses.attribute_type, which is a long string, are combined with transforms. During Suricata startup or rule reload, this combination can trigger a stack buffer overflow due to improper handling of the transformed attribute_type data, leading to memory corruption. This vulnerability is classified under CWE-121, which pertains to stack-based buffer overflows, a common and dangerous class of memory corruption issues that can lead to application crashes or potentially arbitrary code execution. The issue was addressed and fixed in Suricata version 8.0.1. Until upgrading, users can mitigate the risk by disabling rules that include ldap.responses.attribute_type with transforms. The CVSS v3.1 base score is 6.2, indicating a medium severity level. The vector indicates local attack vector (AV:L), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), no impact on confidentiality or integrity (C:N/I:N), but high impact on availability (A:H). There are no known exploits in the wild at the time of publication, and no public patch links beyond the version update. This vulnerability primarily affects the availability of Suricata services, potentially causing denial of service during startup or rule reload, which could disrupt network monitoring and security operations.

For European organizations, the impact of this vulnerability can be significant, especially for those relying on Suricata for critical network security monitoring and intrusion detection/prevention. A successful exploitation could cause Suricata to crash or become unresponsive during startup or rule reload, resulting in temporary loss of network visibility and protection. This downtime could be exploited by attackers to conduct undetected malicious activities, such as data exfiltration, lateral movement, or deployment of malware. Organizations in sectors with high regulatory and compliance requirements, such as finance, healthcare, and critical infrastructure, may face increased risk due to potential gaps in network defense. Additionally, the local attack vector implies that an attacker would need access to the system running Suricata or the ability to trigger rule reloads locally, which may limit remote exploitation but still poses a risk from insider threats or compromised internal hosts. The lack of impact on confidentiality and integrity reduces the risk of direct data compromise through this vulnerability alone, but the availability impact can indirectly affect overall security posture and incident response capabilities.

To mitigate this vulnerability, European organizations should prioritize upgrading Suricata to version 8.0.1 or later, where the issue is fixed. Until the upgrade can be performed, administrators should disable any IDS/IPS rules that use the ldap.responses.attribute_type keyword combined with transforms, as these are the trigger for the buffer overflow. It is important to audit existing rule sets to identify and isolate such rules. Additionally, organizations should restrict local access to Suricata hosts to trusted personnel only, minimizing the risk of local exploitation. Implementing strict access controls and monitoring for unusual rule reload activities can help detect potential exploitation attempts. Regular backups of Suricata configurations and rulesets are recommended to enable quick recovery in case of crashes. Finally, maintaining an up-to-date inventory of Suricata deployments and integrating vulnerability management processes to track and remediate such issues promptly will enhance resilience against similar threats.