CVE-2024-7774: Langchain.js Path Traversal Vulnerability

CVE-2024-7774 Overview

A path traversal vulnerability exists in the getFullPath method of langchain-ai/langchainjs version 0.2.5. This vulnerability allows attackers to save files anywhere in the filesystem, overwrite existing text files, read .txt files, and delete files. The vulnerability is exploited through the setFileContent, getParsedFile, and mdelete methods, which do not properly sanitize user input.

Critical Impact

Attackers can exploit this path traversal vulnerability to read, write, and delete arbitrary files on the filesystem, potentially leading to data exfiltration, system compromise, or denial of service through file deletion.

Affected Products

• langchain langchain.js version 0.2.5
• Applications utilizing LangChain.js file handling methods
• Systems with LangChain.js deployments exposed to untrusted input

Discovery Timeline

• 2024-10-29 - CVE CVE-2024-7774 published to NVD
• 2025-05-28 - Last updated in NVD database

Technical Details for CVE-2024-7774

Vulnerability Analysis

This path traversal vulnerability (CWE-22, CWE-29) stems from improper input validation in the getFullPath method within LangChain.js. The vulnerability affects file handling operations where user-controlled input is passed to file system operations without adequate sanitization. When an attacker supplies specially crafted path sequences containing directory traversal characters (such as ../), the application fails to constrain the resulting file path to the intended directory.

The impact of this vulnerability is significant: attackers can perform unauthorized file operations across the entire filesystem accessible to the running process. This includes reading sensitive configuration files, overwriting application data, and deleting critical system or application files. The network-accessible nature of this vulnerability means remote attackers can exploit it without requiring any authentication or user interaction.

Root Cause

The root cause lies in the getFullPath method's failure to properly sanitize and validate user-supplied path components before constructing filesystem paths. The affected methods—setFileContent, getParsedFile, and mdelete—all rely on getFullPath for path resolution, propagating the vulnerability across multiple file operations. Without proper canonicalization and path boundary checks, directory traversal sequences bypass intended directory restrictions.

Attack Vector

The vulnerability is exploited through network-accessible interfaces that accept file path parameters. An attacker can craft malicious requests containing path traversal sequences to escape the application's intended working directory. The three primary attack surfaces are:

1. File Write via setFileContent: Attackers can save arbitrary content to any writable location on the filesystem, potentially overwriting configuration files or injecting malicious code.

2. File Read via getParsedFile: Attackers can read the contents of .txt files anywhere on the filesystem, enabling data exfiltration of sensitive information.

3. File Deletion via mdelete: Attackers can delete files, causing data loss or denial of service by removing critical application or system files.

The attack requires no authentication and no user interaction, making it highly exploitable in exposed deployments. An attacker would construct path parameters containing sequences like ../../etc/passwd or ..\\..\\windows\\system32\\ (depending on the operating system) to traverse outside the intended directory boundaries.

Detection Methods for CVE-2024-7774

Indicators of Compromise

• Unusual file access patterns in application logs showing path traversal sequences (../, ..\)
• Unexpected file modifications or deletions outside the application's working directory
• Log entries containing path manipulation attempts in file-related API endpoints
• Evidence of sensitive file access from LangChain.js process contexts

Detection Strategies

• Monitor web application logs for requests containing directory traversal patterns such as ../, ..%2f, or URL-encoded variants
• Implement file integrity monitoring on critical system and configuration files
• Deploy web application firewalls (WAF) with path traversal detection rules enabled
• Audit LangChain.js application endpoints that accept file path parameters

Monitoring Recommendations

• Enable verbose logging for all file system operations in LangChain.js applications
• Set up alerts for file access attempts outside designated application directories
• Monitor process file descriptors for unexpected file handles to sensitive paths
• Implement real-time security monitoring for path traversal indicators in HTTP request parameters

How to Mitigate CVE-2024-7774

Immediate Actions Required

• Upgrade langchain.js to a patched version that includes the security fix
• Audit existing deployments to identify any evidence of exploitation
• Implement input validation on all file path parameters as a defense-in-depth measure
• Review application permissions to ensure minimal filesystem access rights

Patch Information

LangChain has released a security patch addressing this vulnerability. The fix is available in the GitHub commit a0fad77d6b569e5872bd4a9d33be0c0785e538a9. Organizations should upgrade to the patched version immediately. Additional technical details about this vulnerability can be found in the Huntr bounty report.

Workarounds

• Implement strict input validation to reject any path containing traversal sequences before passing to LangChain.js methods
• Use path canonicalization and verify the resulting path remains within allowed directories
• Run LangChain.js applications with minimal filesystem permissions using principle of least privilege
• Consider containerization or sandboxing to limit filesystem access scope

# Configuration example
# Verify your langchain.js version and update if vulnerable
npm list langchain
npm update langchain

# If using yarn
yarn info langchain version
yarn upgrade langchain