CVE-2026-45751 in Suricata
Summary
by MITRE • 09/11/2026
Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring engine. Prior to versions 7.0.16 and 8.0.5, Suricata's inspection-buffer helper could leave an inspection pointer referencing freed memory after a chained transform caused the backing buffer to be reallocated. The issue is reached during a specific network traffic processing, and requires a specific but not malicious rule. Versions 7.0.16 and 8.0.5 contain a fix. As a workaround, avoid rules that chain `dotprefix` transform after another one.
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Analysis
by VulDB Data Team • 09/11/2026
Suricata serves as a critical component in modern network security infrastructure, functioning simultaneously as an Intrusion Detection System, an Intrusion Prevention System, and a Network Security Monitoring engine. Its primary role involves deep packet inspection to identify malicious activity or policy violations within network traffic streams. The software relies on complex data structures to manage the state of connections and payloads during analysis. A significant architectural flaw was identified in versions prior to 7.0.16 and 8.0.5, specifically within the inspection-buffer helper mechanism that manages memory allocation for packet payload processing. This vulnerability represents a classic use-after-free condition where an internal pointer remains valid after its underlying memory has been deallocated or reallocated by the system.
The technical root cause of this vulnerability lies in how Suricata handles chained string transforms during rule evaluation. When network traffic matches specific rules that utilize multiple transformations, such as chaining a dotprefix transform after another transformation, the engine may trigger a buffer reallocation to accommodate modified payload data. During this process, an inspection pointer intended to reference the current state of the inspected data fails to update correctly when the backing memory is moved or freed. Consequently, subsequent operations attempt to access memory at the old address, which no longer holds the expected data structure. This results in a dangling pointer scenario where the application reads from or writes to invalid memory locations, leading to undefined behavior that can manifest as crashes, data corruption, or potentially arbitrary code execution depending on the specific context of the memory layout and attacker control over adjacent heap structures.
From an operational perspective, this vulnerability requires precise conditions to be exploited. It is not triggered by malicious payloads in the traditional sense but rather by legitimate network traffic that matches rules employing specific chained transforms. The requirement for a non-malicious rule means that attackers could potentially trigger the flaw through normal business traffic if such rules are present in the detection policy, or they might craft packets specifically designed to hit these transformation chains without necessarily containing exploit code themselves. This characteristic makes the vulnerability particularly insidious because it blurs the line between benign configuration errors and active exploitation attempts. The impact ranges from denial of service due to application crashes to more severe security breaches if an attacker can leverage the memory corruption to execute arbitrary commands on the host running Suricata, thereby compromising the integrity of the entire network monitoring infrastructure.
To mitigate this risk, immediate action is required for organizations operating affected versions of Suricata. The primary and most effective mitigation strategy involves upgrading to version 7.0.16 or 8.0.5, which contain the necessary code corrections to properly manage pointer updates during buffer reallocation events. For environments where an immediate upgrade is not feasible due to operational constraints, a workaround exists in the rule configuration itself. Administrators should audit their detection rules and avoid chaining dotprefix transforms after other transformations until patches can be applied. This restriction prevents the specific sequence of operations that triggers the memory management error. Additionally, enabling strict logging and monitoring for unexpected Suricata process restarts or segmentation faults can help detect potential exploitation attempts in real-time while mitigation strategies are being implemented.
This vulnerability aligns with Common Weakness Enumeration identifier CWE-416, which describes use after free errors resulting from improper handling of memory deallocation relative to pointer validity. In the context of the MITRE ATT&CK framework, this flaw could be leveraged during techniques associated with privilege escalation or defense evasion if an attacker successfully achieves code execution on the monitoring host. The incident underscores the importance of rigorous memory safety practices in high-performance network security appliances and highlights how complex rule processing logic can introduce subtle but critical vulnerabilities when state management is not meticulously maintained across dynamic memory operations.