CVE-2024-5986 in h2o-3
Summary
by MITRE • 02/02/2026
A vulnerability in h2oai/h2o-3 version 3.46.0.1 allows remote attackers to write arbitrary data to any file on the server. This is achieved by exploiting the `/3/Parse` endpoint to inject attacker-controlled data as the header of an empty file, which is then exported using the `/3/Frames/framename/export` endpoint. The impact of this vulnerability includes the potential for remote code execution and complete access to the system running h2o-3, as attackers can overwrite critical files such as private SSH keys or script files.
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Analysis
by VulDB Data Team • 02/02/2026
The vulnerability identified as CVE-2024-5986 represents a critical path traversal and arbitrary file write flaw within the h2o-3 machine learning platform version 3.46.0.1. This vulnerability exists due to insufficient input validation and sanitization within the h2o-3 REST API endpoints, specifically targeting the `/3/Parse` and `/3/Frames/framename/export` endpoints. The flaw stems from the platform's failure to properly validate user-supplied data when processing file headers, creating an opportunity for remote attackers to manipulate the system's file handling mechanisms. Security researchers have classified this vulnerability under CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal attacks. The exploitation chain begins with an attacker sending malicious data to the `/3/Parse` endpoint where the system accepts and processes user-controlled input as file header information. This input is then stored in a temporary file structure that can later be accessed through the `/3/Frames/framename/export` endpoint, allowing the attacker to control the content of exported files. The implications of this vulnerability extend beyond simple file manipulation, as it creates a pathway for complete system compromise through remote code execution capabilities.
The operational impact of CVE-2024-5986 is severe and multifaceted, potentially enabling attackers to achieve full system control over affected h2o-3 instances. When attackers successfully exploit this vulnerability, they can overwrite critical system files including private SSH keys, configuration scripts, and other sensitive artifacts that are essential for system integrity and security. This capability allows for persistent access and privilege escalation within the compromised environment, making it particularly dangerous for organizations that rely on h2o-3 for data processing and machine learning workloads. The vulnerability's potential for remote code execution means that attackers can deploy malicious payloads directly on the target system without requiring additional attack vectors or exploitation techniques. The threat landscape for this vulnerability aligns with ATT&CK technique T1059.007, which covers scripting languages for execution, as attackers could leverage this vulnerability to inject and execute malicious code within the h2o-3 environment. Organizations running vulnerable versions of h2o-3 face significant risk of data breaches, system compromise, and potential lateral movement within their networks, particularly when these systems are accessible from untrusted networks.
Mitigation strategies for CVE-2024-5986 should prioritize immediate patching and implementation of network-level controls to prevent unauthorized access to the affected endpoints. Organizations must update their h2o-3 installations to versions that address this vulnerability, as the vendor has likely released security patches to resolve the input validation issues within the affected API endpoints. Network segmentation and access controls should be implemented to restrict access to the `/3/Parse` and `/3/Frames/framename/export` endpoints, particularly limiting these capabilities to trusted administrative users only. Input validation should be strengthened at multiple layers including API gateway level and application level to prevent malicious data from being processed as file headers. Additionally, organizations should implement monitoring and logging for these specific endpoints to detect anomalous usage patterns that might indicate exploitation attempts. The implementation of principle of least privilege should be enforced for h2o-3 service accounts, limiting their file system access to only necessary directories and preventing write access to critical system files. Security teams should also consider implementing web application firewalls to filter potentially malicious requests targeting these vulnerable endpoints, as this approach can provide an additional layer of protection against exploitation attempts. Regular security assessments and penetration testing should be conducted to verify that the implemented mitigations are effective against potential attack vectors targeting this vulnerability.