CVE-2026-7403 Overview
A path traversal vulnerability has been discovered in geldata gel-mcp version 0.1.0. This security flaw impacts the list_rules and fetch_rule functions located in the file src/gel_mcp/server.py. By manipulating the rule_name argument, an attacker can traverse directory paths to access files outside the intended directory structure. The attack can be performed remotely over the network without requiring authentication.
Critical Impact
Remote attackers can exploit this path traversal vulnerability to read arbitrary files on the server by manipulating the rule_name parameter, potentially exposing sensitive configuration data, credentials, or other protected information.
Affected Products
- geldata gel-mcp 0.1.0
Discovery Timeline
- 2026-04-29 - CVE CVE-2026-7403 published to NVD
- 2026-04-29 - Last updated in NVD database
Technical Details for CVE-2026-7403
Vulnerability Analysis
This path traversal vulnerability (CWE-22) exists in the geldata gel-mcp Python package, specifically within the server component responsible for rule management. The vulnerable functions list_rules and fetch_rule in src/gel_mcp/server.py fail to properly sanitize the rule_name parameter before using it to construct file paths.
When user-supplied input is incorporated into file path operations without adequate validation, attackers can use directory traversal sequences (such as ../) to escape the intended directory and access files elsewhere on the filesystem. This vulnerability is accessible over the network, requiring no authentication and no user interaction to exploit.
The exploit has been publicly disclosed and may be used for attacks. The project maintainers were notified early through a GitHub issue report, but as of the CVE publication date, no response has been received.
Root Cause
The root cause of this vulnerability is improper input validation in the rule_name parameter handling. The list_rules and fetch_rule functions in src/gel_mcp/server.py directly incorporate user-supplied input into filesystem operations without sanitizing path traversal sequences. This allows attackers to manipulate the rule_name argument to include relative path components that navigate outside the expected directory boundary.
Attack Vector
The attack can be executed remotely over the network. An attacker sends a crafted request containing directory traversal sequences in the rule_name parameter. For example, by supplying values like ../../../etc/passwd as the rule_name, an attacker could potentially read sensitive system files or application configuration data.
The exploitation does not require any special privileges or user interaction, making it straightforward to execute. Since the exploit details have been publicly released, organizations using the affected version should treat this as an urgent security concern.
For technical details and proof-of-concept information, refer to the VulDB vulnerability entry and the GitHub issue tracker.
Detection Methods for CVE-2026-7403
Indicators of Compromise
- HTTP requests or API calls containing path traversal sequences (../, ..\, %2e%2e%2f, %2e%2e/) in the rule_name parameter
- Unusual file access patterns in web server or application logs indicating attempts to read files outside the rules directory
- Error messages or log entries showing failed attempts to access system files like /etc/passwd or Windows system paths
Detection Strategies
- Implement web application firewall (WAF) rules to detect and block requests containing path traversal patterns in API parameters
- Configure intrusion detection systems (IDS) to alert on network traffic containing directory traversal sequences targeting gel-mcp endpoints
- Deploy application-level logging to capture all rule_name parameter values and flag suspicious patterns for review
Monitoring Recommendations
- Enable detailed logging for the gel-mcp application and monitor for requests to the list_rules and fetch_rule endpoints
- Set up alerts for any file access attempts outside the designated rules directory
- Monitor for unusual patterns of failed file access operations that may indicate reconnaissance or exploitation attempts
How to Mitigate CVE-2026-7403
Immediate Actions Required
- Review all deployments of geldata gel-mcp 0.1.0 and assess exposure to untrusted network access
- Implement network-level restrictions to limit access to the affected service to trusted sources only
- Deploy web application firewall rules to block requests containing path traversal sequences
- Monitor logs for any signs of exploitation attempts
Patch Information
As of the CVE publication date, no official patch has been released by the vendor. The project was notified through a GitHub issue but has not yet responded. Users should monitor the gel-mcp GitHub repository for security updates and apply patches as soon as they become available.
Workarounds
- Restrict network access to the gel-mcp service using firewall rules, allowing only trusted IP addresses
- Implement input validation at the application proxy or gateway level to reject any rule_name values containing path traversal characters
- Consider disabling the list_rules and fetch_rule functionality if not critical to operations until a patch is available
- Deploy the application in a sandboxed environment with minimal filesystem permissions to limit potential damage from exploitation
# Example: Network-level restriction using iptables
# Restrict access to gel-mcp service (adjust port as needed)
iptables -A INPUT -p tcp --dport 8080 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 8080 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
