CVE-2025-64333 is a stack-based buffer overflow vulnerability identified in the Suricata network IDS/IPS/NSM engine maintained by the Open Information Security Foundation (OISF). The vulnerability arises when Suricata processes and logs an unusually large HTTP content type, which causes a stack overflow leading to a crash of the Suricata process. This issue affects versions prior to 7.0.13 and 8.0.2, where the vulnerability has been patched. The root cause is related to improper handling of large HTTP content types during logging, which overflows the stack buffer. The vulnerability is classified under CWE-121 (Stack-based Buffer Overflow). Exploitation can be performed remotely without authentication or user interaction, by sending crafted HTTP traffic that triggers the overflow. The impact is primarily on availability, as the overflow causes Suricata to crash, potentially leading to denial of service in network monitoring and intrusion detection capabilities. Workarounds include limiting the stream.reassembly.depth configuration parameter to less than half the stack size or increasing the process stack size to reduce the chance of overflow. No known exploits have been reported in the wild as of the publication date. The CVSS v3.1 base score is 7.5, reflecting a high severity due to network attack vector, low attack complexity, no privileges required, no user interaction, and a significant impact on availability.

For European organizations, the primary impact of CVE-2025-64333 is on the availability and reliability of network security monitoring and intrusion detection systems that use Suricata. A successful exploit can cause Suricata to crash, resulting in loss of visibility into network traffic and potential blind spots in threat detection. This can increase the risk of undetected attacks or breaches, especially in critical sectors such as finance, telecommunications, energy, and government. The disruption may also affect incident response capabilities and compliance with regulatory requirements for network monitoring. Organizations relying heavily on Suricata for real-time intrusion prevention may experience service interruptions or degraded security posture. Given the ease of exploitation and remote attack vector, attackers could launch denial-of-service attacks against Suricata deployments, potentially as part of larger multi-stage attacks. The lack of confidentiality or integrity impact reduces the risk of data compromise directly from this vulnerability, but the availability impact alone is significant for operational security.

The most effective mitigation is to upgrade Suricata to versions 7.0.13 or 8.0.2, where the vulnerability has been patched. Organizations unable to immediately upgrade should implement the following specific mitigations: 1) Configure the stream.reassembly.depth parameter to a value less than half the process stack size to reduce the likelihood of triggering the overflow. 2) Increase the process stack size where possible to make stack overflow less probable. 3) Monitor Suricata logs and system stability for crashes or anomalies that may indicate exploitation attempts. 4) Employ network-level protections such as rate limiting or filtering to restrict large or suspicious HTTP content types that could trigger the vulnerability. 5) Maintain up-to-date intrusion detection signatures and anomaly detection to identify attempts to exploit this vulnerability. 6) Conduct regular security assessments and penetration testing to validate the effectiveness of mitigations. 7) Ensure incident response plans include procedures for Suricata service disruptions and rapid recovery. These targeted mitigations go beyond generic advice by focusing on configuration tuning and operational monitoring specific to this vulnerability.