CVE-2026-30351: Autocoder Path Traversal Vulnerability

CVE-2026-30351 Overview

A path traversal vulnerability exists in the UI/static component of leonvanzyl autocoder at commit 79d02a. This vulnerability allows remote attackers to read arbitrary files from the server by sending crafted URL paths containing directory traversal sequences. The flaw stems from improper validation of user-supplied input in the static file serving functionality, enabling attackers to escape the intended directory and access sensitive files elsewhere on the filesystem.

Critical Impact
Unauthenticated remote attackers can read arbitrary files from affected servers, potentially exposing sensitive configuration files, credentials, source code, and other confidential data.

Affected Products

leonvanzyl autocoder commit 79d02a

Discovery Timeline

2026-04-27 - CVE CVE-2026-30351 published to NVD
2026-04-27 - Last updated in NVD database

Technical Details for CVE-2026-30351

Vulnerability Analysis

This path traversal vulnerability (CWE-22) resides in the UI/static component of the autocoder application. The vulnerable code fails to properly sanitize file path inputs when serving static files, allowing attackers to include directory traversal sequences such as ../ in their requests. By chaining multiple traversal sequences, an attacker can navigate outside the web root directory and access files anywhere on the filesystem that the web server process has read permissions to access.

The attack requires no authentication and can be executed remotely over the network, making it particularly dangerous for internet-facing deployments. While this vulnerability allows reading of arbitrary files, it does not enable modification or deletion of files, limiting the impact to confidentiality compromise.

Root Cause

The root cause of this vulnerability is insufficient input validation and path canonicalization in the static file serving component. The application does not properly sanitize user-supplied path components before using them to construct file system paths. Specifically, the code fails to:

Normalize the requested path to remove traversal sequences
Validate that the resolved path remains within the intended static files directory
Implement proper sandboxing or chroot restrictions for file access

Attack Vector

The attack vector is network-based and requires no user interaction or authentication. An attacker can exploit this vulnerability by sending an HTTP request to the vulnerable static file endpoint with a specially crafted URL path containing directory traversal sequences (e.g., ../../../etc/passwd).

The traversal sequences allow the attacker to navigate up the directory tree from the static files directory and then descend into other directories on the system. Common targets include:

System configuration files (e.g., /etc/passwd, /etc/shadow)
Application configuration files containing credentials
Environment files with API keys and secrets
Source code files that may reveal additional vulnerabilities

Technical details and proof-of-concept information are available in the GitHub Gist PoC Repository.

Detection Methods for CVE-2026-30351

Indicators of Compromise

HTTP requests to static endpoints containing ../ or ..%2f sequences
Access log entries showing requests for system files like /etc/passwd or Windows system files
Unusual file access patterns in application or system logs
Requests with URL-encoded traversal sequences such as %2e%2e%2f or double-encoding variations

Detection Strategies

Deploy Web Application Firewall (WAF) rules to detect and block path traversal patterns in URL paths
Monitor web server access logs for requests containing directory traversal sequences
Implement file integrity monitoring on sensitive system and configuration files
Use intrusion detection systems (IDS) with signatures for path traversal attack patterns
Enable verbose logging on the autocoder application to capture suspicious file access attempts

Monitoring Recommendations

Set up real-time alerts for any HTTP requests containing ../ patterns targeting the static endpoint
Monitor for failed file access attempts in application logs that may indicate traversal attacks
Implement anomaly detection for unusual patterns of static file requests
Review web server logs regularly for evidence of reconnaissance or exploitation attempts

How to Mitigate CVE-2026-30351

Immediate Actions Required

Update to a patched version of autocoder if one is available from the GitHub Tool Repository
Restrict network access to the application to trusted networks only until patched
Deploy WAF rules to block requests containing path traversal sequences
Review access logs for evidence of prior exploitation attempts
Consider temporarily disabling the static file serving functionality if not critical to operations

Patch Information

As of the last NVD update on 2026-04-27, affected users should monitor the GitHub Tool Repository for security updates. The vulnerability affects commit 79d02a, and users should update to any newer commits that address this path traversal issue once available.

Workarounds

Implement a reverse proxy (such as nginx or Apache) in front of the application with path traversal filtering rules
Configure the web server to use chroot or similar sandboxing to restrict file system access
Use application-level input validation to reject requests containing traversal sequences before they reach the vulnerable component
Restrict the application's file system permissions to limit readable files to only those necessary for operation
Deploy network segmentation to limit exposure of vulnerable systems to untrusted networks

bash

# Example nginx configuration to block path traversal attempts
location /static/ {
    # Block requests containing path traversal sequences
    if ($request_uri ~* "\.\.") {
        return 403;
    }
    
    # Serve static files from restricted directory
    alias /var/www/autocoder/static/;
    
    # Disable symlink following for additional protection
    disable_symlinks on;
}