CVE-2026-18348 in Velociraptor
Summary
by MITRE • 08/11/2026
Missing authorization check in the upload_azure, upload_sftp, and upload_smb VQL plugins allows an authenticated analyst-role user can initiate attacker-controlled outbound network connections from the Velociraptor server, bypassing the NETWORK ACL permission boundary. This enables internal network reconnaissance via port oracle and potential data exfiltration to external endpoints.
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Analysis
by VulDB Data Team • 08/11/2026
This vulnerability represents a critical authorization flaw in the Velociraptor incident response platform that fundamentally undermines network security boundaries through improperly validated file upload operations. The issue affects three core VQL plugins - upload_azure, upload_sftp, and upload_smb - which are designed to handle outbound file transfers from the Velociraptor server to remote storage systems. When an authenticated user with analyst privileges attempts to execute these upload operations, the system fails to validate whether the destination endpoint falls within the configured network access control list boundaries, creating a direct pathway for malicious actors to establish unauthorized outbound connections. This missing authorization check constitutes a severe violation of the principle of least privilege and represents a clear deviation from secure coding practices that should prevent authenticated users from bypassing network access controls.
The technical implementation flaw stems from inadequate input validation within the upload plugin architecture where destination parameters are not properly sanitized or validated against configured network ACLs before establishing outbound connections. The vulnerability allows an attacker to specify arbitrary destination endpoints, enabling them to initiate connections to external systems regardless of the server's network restrictions. This creates a persistent threat vector where even users with minimal privileges can leverage the legitimate file upload functionality to perform reconnaissance activities such as port scanning against internal systems through what is known as port oracle techniques. The attacker can systematically test various ports and services within the internal network to identify open endpoints that may contain vulnerable services or sensitive information, effectively using the Velociraptor server as a pivot point for internal network exploration.
The operational impact of this vulnerability extends beyond simple reconnaissance to enable potential data exfiltration capabilities that could compromise sensitive organizational assets. Once an attacker establishes outbound connectivity through the upload plugins, they can potentially exfiltrate collected forensic data, system information, or other sensitive artifacts from the Velociraptor server to external command and control servers. The vulnerability affects the fundamental security model of the platform by allowing users with analyst roles to bypass network segmentation controls that are typically enforced at the server level. This creates a significant risk for organizations that rely on network ACLs as part of their defense-in-depth strategy, as the vulnerability essentially provides a backdoor mechanism that circumvents these protections entirely.
Organizations should implement immediate mitigations including restricting access to the affected VQL plugins through role-based access controls, implementing additional authorization checks within the upload plugin code, and monitoring for unusual outbound connection patterns from Velociraptor servers. The vulnerability aligns with CWE-639 Access Control Bypass and maps to ATT&CK technique T1071.004 Application Layer Protocol: DNS where attackers may use the compromised upload functionality to establish covert communication channels. Regular auditing of network connections initiated by Velociraptor servers should be implemented to detect potential exploitation attempts, while implementing network segmentation controls that limit outbound access even for legitimate administrative functions. The remediation process requires patching the upload plugin code to enforce strict destination validation against configured network ACLs and ensuring that all file transfer operations require explicit authorization before establishing connections to external endpoints, thereby restoring proper boundary enforcement within the Velociraptor platform architecture.