CVE-2026-92604 in Scirius
Summary
by MITRE • 09/16/2026
Scirius through 3.8.0 contains an arbitrary file write vulnerability in the PCAP filestore upload endpoint that allows default User role users to write attacker-controlled JSON content to filesystem paths. Attackers can supply path traversal sequences in the uploaded document's _id field to escape the intended directory and write files with .json extension to arbitrary locations as root.
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Analysis
by VulDB Data Team • 09/16/2026
Scirius, a web-based network security monitoring tool that serves as a graphical interface for Zeek intrusion detection systems, contains a critical vulnerability identified through version 3.8.0 involving an insecure file handling mechanism within its PCAP filestore upload endpoint. This flaw manifests as an arbitrary file write vulnerability, which fundamentally compromises the integrity and availability of the underlying operating system by allowing unauthorized actors to manipulate filesystem contents in ways not intended by the application design. The root cause lies in the insufficient validation and sanitization of user-supplied input fields during the processing of uploaded PCAP files. Specifically, the _id field within the JSON metadata associated with the upload request is processed without adequate checks for path traversal sequences or directory boundary constraints. This lack of rigorous input validation permits an attacker to inject maliciously crafted strings that exploit standard filesystem navigation characters, thereby bypassing the intended isolation boundaries established by the application's storage architecture.
The operational impact of this vulnerability is severe due to the privilege context in which Scirius typically operates. In many deployment scenarios, particularly those involving system-level network monitoring and packet capture analysis, the service runs with elevated privileges or as root to ensure access to raw network interfaces and sensitive log files. Consequently, when an attacker supplies path traversal sequences such as dot-dot-slash patterns within the _id field of the uploaded document's metadata, they can escape the designated upload directory. This allows them to write arbitrary JSON content to filesystem paths outside the application's sandboxed environment. Because the file is written with a .json extension and executed or processed by components running under high-privilege accounts, this action effectively grants the attacker remote code execution capabilities on the host system. The ability to write files as root means that an adversary can place web shells, modify configuration files, install backdoors, or alter critical system binaries, leading to a complete compromise of the target infrastructure.
From a classification perspective, this vulnerability aligns with CWE-434, which describes the unrestricted upload of file with dangerous type, and more specifically CWE-22, the improper limitation of a pathname to a restricted directory, also known as Path Traversal. The exploitation technique leverages the application's failure to properly neutralize special elements that could be interpreted by the operating system's filesystem parser. In terms of offensive security frameworks, this activity maps directly to MITRE ATT&CK techniques related to File and Directory Discovery followed by Command and Scripting Interpreter execution via file write operations. Attackers can utilize this vector for initial access if combined with other authentication bypasses or lateral movement if used to plant persistent backdoors within system directories that are monitored less frequently than web-accessible folders.
Mitigation strategies must address both the immediate technical flaw and broader security posture improvements. The primary remediation involves implementing strict input validation on all user-supplied fields, particularly those influencing file paths or names. Developers should enforce allowlisting for filename characters and ensure that any provided path is resolved to an absolute canonical path before being used in filesystem operations. This process must include a verification step confirming that the resulting canonical path resides within the expected upload directory, thereby neutralizing traversal sequences regardless of their encoding or format. Additionally, applying principle of least privilege is essential; Scirius should be configured to run with minimal necessary permissions, avoiding root access where possible by using dedicated service accounts with restricted filesystem rights. Regular security audits and static code analysis tools focused on file handling operations can help identify similar vulnerabilities in other parts of the application stack before they are exploited in production environments.