CVE-2026-19366 Overview
CVE-2026-19366 is a path traversal vulnerability in NocteDefensor LudusMCP versions up to 1.0.24. The flaw resides in the insert_creds_range_config component, specifically within the src/tools/insertCredsRangeConfig.ts file. An attacker with local access can manipulate the configPath or outputPath arguments to traverse directories outside the intended scope. The weakness is classified as [CWE-22] Improper Limitation of a Pathname to a Restricted Directory. According to the reporter, the project maintainer was notified through a public issue report but has not yet responded.
Critical Impact
A local authenticated user can read or write files outside the intended directory by injecting traversal sequences into the configPath or outputPath arguments processed by insertCredsRangeConfig.ts.
Affected Products
- NocteDefensor LudusMCP versions up to and including 1.0.24
- Component: insert_creds_range_config
- File: src/tools/insertCredsRangeConfig.ts
Discovery Timeline
- 2026-08-09 - CVE-2026-19366 published to NVD
- 2026-08-13 - Last updated in NVD database
Technical Details for CVE-2026-19366
Vulnerability Analysis
The vulnerability affects the LudusMCP tool at src/tools/insertCredsRangeConfig.ts, which handles credential range configuration input. The insert_creds_range_config component accepts user-controlled configPath and outputPath arguments without sufficient validation. An attacker can supply traversal sequences such as ../ to reference files outside the expected working directory. This enables reading arbitrary configuration files or writing credential data to unintended filesystem locations.
Exploitation requires local execution privileges on the host running LudusMCP. The impact is bounded to confidentiality, integrity, and availability of files accessible under the process's user context. Because MCP tooling frequently runs with the developer's or operator's credentials, traversal can expose sensitive artifacts including SSH keys, environment files, or lab credential stores. See the GitHub issue and VulDB entry for additional context.
Root Cause
The root cause is missing canonicalization and allow-list validation of filesystem path arguments. The handler passes configPath and outputPath directly to filesystem APIs without normalizing them against a fixed base directory or rejecting parent-directory references.
Attack Vector
The attack vector is local. An attacker who can invoke the insert_creds_range_config tool supplies a crafted path such as ../../../etc/hosts or ../../.ssh/authorized_keys as configPath or outputPath. The tool then reads from or writes to that location using the privileges of the running process.
See the LudusMCP GitHub repository and VulDB references for technical details.
No verified exploit code is published at time of writing.
Detection Methods for CVE-2026-19366
Indicators of Compromise
- Invocations of the insert_creds_range_config tool containing ../ or absolute paths outside the LudusMCP working directory
- Unexpected reads or writes to sensitive files such as ~/.ssh/, /etc/, or credential stores by the Node.js process hosting LudusMCP
- New or modified files in directories the LudusMCP tool should not touch, timestamped near tool invocation
Detection Strategies
- Enable filesystem auditing on hosts running LudusMCP and correlate file access events with the Node.js process ID
- Review LudusMCP application logs for configPath or outputPath argument values containing traversal sequences or paths that resolve outside the expected base directory
- Alert on Node.js child processes reading files outside the project directory when the parent command line references insertCredsRangeConfig
Monitoring Recommendations
- Monitor host telemetry for path-traversal patterns in command arguments and JSON tool inputs on developer and lab hosts
- Track file integrity for sensitive directories such as /etc, user home directories, and lab credential stores on systems where LudusMCP is installed
- Baseline expected file access by LudusMCP and flag deviations, particularly writes to non-project paths
How to Mitigate CVE-2026-19366
Immediate Actions Required
- Restrict access to hosts running LudusMCP to trusted local users only, since exploitation requires local invocation
- Run LudusMCP under a dedicated low-privilege account that cannot read or write sensitive system or user files
- Audit prior invocations of insert_creds_range_config for suspicious configPath or outputPath values
Patch Information
No vendor patch is available at the time of publication. The upstream issue #5 documents the report, and the maintainer has not yet responded. Users should monitor the LudusMCP repository for a fixed release.
Workarounds
- Wrap or fork insertCredsRangeConfig.ts to canonicalize input paths with path.resolve and reject any result that does not begin with the intended base directory
- Enforce an allow-list of permitted directories for configPath and outputPath inputs
- Apply operating-system level access controls such as AppArmor, SELinux, or filesystem ACLs to constrain the LudusMCP process to its project directory
# Example: run LudusMCP under a dedicated user with a chroot-style working directory
sudo useradd -r -m -d /opt/ludusmcp ludus
sudo chown -R ludus:ludus /opt/ludusmcp
sudo -u ludus node /opt/ludusmcp/dist/index.js
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
