CVE-2026-26933 in Packetbeat
Summary
by MITRE • 03/19/2026
Improper Validation of Array Index (CWE-129) in multiple protocol parser components in Packetbeat can lead Denial of Service via Input Data Manipulation (CAPEC-153). An attacker with the ability to send specially crafted, malformed network packets to a monitored network interface can trigger out-of-bounds read operations, resulting in application crashes or resource exhaustion. This requires the attacker to be positioned on the same network segment as the Packetbeat deployment or to control traffic routed to monitored interfaces.
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Analysis
by VulDB Data Team • 03/24/2026
The vulnerability identified as CVE-2026-26933 represents a critical weakness in Packetbeat's protocol parsing capabilities that stems from improper validation of array indices. This flaw falls under the Common Weakness Enumeration category 129, which specifically addresses issues related to the validation of array indices and their subsequent access patterns. The vulnerability manifests within multiple protocol parser components that are responsible for analyzing network traffic and extracting meaningful data for monitoring and alerting purposes. When these parsers encounter malformed network packets, they fail to properly validate array bounds before accessing memory locations, creating a pathway for malicious input to cause unintended behavior.
The operational impact of this vulnerability extends beyond simple application instability to encompass potential system-wide denial of service conditions. An attacker positioned within the same network segment as a Packetbeat deployment or capable of manipulating traffic routed to monitored interfaces can exploit this weakness by crafting specifically designed network packets that trigger out-of-bounds read operations. These operations can cause the Packetbeat application to crash or enter an unstable state where it consumes excessive system resources, effectively rendering the network monitoring capabilities ineffective. The vulnerability's exploitation requires minimal privileges and can be executed against any network interface that Packetbeat is configured to monitor, making it particularly dangerous in environments where network monitoring is critical for security operations.
From a cybersecurity perspective, this vulnerability aligns with the CAPEC-153 category of Input Data Manipulation attacks, where malicious actors manipulate input data to cause unexpected behavior in network monitoring tools. The attack vector demonstrates the classic characteristics of a remote code execution threat that has been mitigated to a denial of service condition due to the nature of the array index validation failure. The attack requires the attacker to have network access to the monitored segment, which is a common threat scenario in many enterprise environments where Packetbeat is deployed for security monitoring. The vulnerability's severity is amplified by the fact that Packetbeat is often deployed in security-critical roles where network visibility is essential for detecting and responding to threats.
The technical exploitation of this vulnerability involves crafting network packets that contain malformed data structures which, when parsed by Packetbeat's protocol parsers, cause array indices to exceed valid memory boundaries. This results in memory access violations that can be leveraged to crash the application or cause resource exhaustion through repeated malformed packet injection. The vulnerability affects multiple protocol parsers within Packetbeat, suggesting that the issue is not isolated to a single protocol implementation but rather represents a systemic problem in how the application handles array-based data structures during protocol analysis. Organizations should consider implementing network segmentation and access controls to limit the potential attack surface, while also ensuring that Packetbeat deployments are regularly updated with security patches that address this specific array validation weakness.
Mitigation strategies should include immediate deployment of vendor-provided patches that implement proper array index validation and bounds checking throughout the protocol parser components. Network administrators should also consider implementing additional monitoring for unusual traffic patterns that might indicate exploitation attempts, while establishing network access controls to prevent unauthorized access to segments where Packetbeat is deployed. The vulnerability underscores the importance of input validation in security-critical applications and demonstrates how seemingly minor implementation flaws can have significant operational impacts. Organizations should conduct thorough vulnerability assessments to identify similar weaknesses in other network monitoring tools and ensure that all protocol parsing components include robust validation mechanisms to prevent out-of-bounds memory access operations. This vulnerability serves as a reminder of the critical need for rigorous security testing of network monitoring applications, particularly those handling untrusted input data from network traffic.