CVE-2026-19323 Overview
CVE-2026-19323 is a path traversal vulnerability [CWE-22] in the azer/react-analyzer-mcp project, affecting commits up to 335f2a3585f265e2e88352b59b10d3b478d678b0. The flaw exists in the generateProjectDocs function inside src/index.ts, part of the analyze-project component. Attackers with local access can manipulate the projectName argument to traverse directories outside the intended documentation output path. The project uses a rolling release model, so no fixed version identifiers are available. The maintainer was notified through a public issue report but has not responded.
Critical Impact
Local attackers can leverage unsanitized input in generateProjectDocs to read or write files outside the intended project directory, potentially disclosing or corrupting sensitive files.
Affected Products
- azer/react-analyzer-mcp — commits up to 335f2a3585f265e2e88352b59b10d3b478d678b0
- Component: analyze-project in src/index.ts
- Function: generateProjectDocs
Discovery Timeline
- 2026-08-09 - CVE-2026-19323 published to NVD
- 2026-08-12 - Last updated in NVD database
Technical Details for CVE-2026-19323
Vulnerability Analysis
The vulnerability resides in the generateProjectDocs function of src/index.ts in the react-analyzer-mcp project. This project provides a Model Context Protocol (MCP) server for analyzing React codebases. The projectName argument is consumed and used to construct file system paths without adequate sanitization. An attacker supplies traversal sequences such as ../ to escape the intended output directory. Because the attack requires local access with low privileges, the impact is bounded, but the flaw enables reading or writing to arbitrary paths reachable by the process user. EPSS data reports a low exploitation probability, consistent with the local-only attack requirement and absence of a public exploit.
Root Cause
The root cause is missing path validation and normalization on the projectName parameter before it is joined into a filesystem path. The function trusts caller-supplied input and does not enforce that the resolved path stays within the designated project or documentation directory.
Attack Vector
Exploitation requires local access to the host running react-analyzer-mcp and the ability to invoke the analyze-project component with an attacker-controlled projectName. Supplying a value containing ../ sequences or an absolute path redirects file operations to arbitrary locations. Refer to the GitHub Issue Discussion and VulDB CVE-2026-19323 for technical details.
No verified exploit code is available for this issue. The vulnerability manifests when generateProjectDocs builds output paths by concatenating a base directory with the unsanitized projectName. See the linked references for reproduction context.
Detection Methods for CVE-2026-19323
Indicators of Compromise
- Files written or read outside the expected documentation output directory of the react-analyzer-mcp process.
- Log entries or process telemetry showing projectName values containing ../, ..\, or absolute path prefixes.
- Unexpected creation of .md documentation artifacts in system or user directories unrelated to the analyzer.
Detection Strategies
- Instrument or wrap the analyze-project MCP tool call to log all projectName arguments and flag values containing traversal sequences.
- Perform static analysis of src/index.ts to identify use of path.join or template strings that incorporate projectName without a path.resolve boundary check.
- Monitor filesystem activity of the Node.js process running the MCP server for writes outside its working directory.
Monitoring Recommendations
- Enable audit logging on directories adjacent to the analyzer working path to catch out-of-scope reads and writes.
- Track invocations of the MCP server and alert on argument patterns matching ..[\\/] or paths beginning with / or a drive letter.
- Review GitHub issue #3 for status updates before deploying the tool.
How to Mitigate CVE-2026-19323
Immediate Actions Required
- Restrict local access to hosts running react-analyzer-mcp to trusted users only.
- Run the MCP server under a dedicated low-privilege account with filesystem access limited to the intended project and output directories.
- Validate projectName at the caller by rejecting values containing .., path separators, or non-alphanumeric characters.
Patch Information
No official patch is available. The maintainer has not responded to the public issue report referenced in the GitHub Issue Discussion. Because the project uses a rolling release, monitor the GitHub Repository for React Analyzer for future commits addressing input validation on projectName.
Workarounds
- Fork the repository and add an allowlist regex such as ^[A-Za-z0-9_-]+$ for projectName before it reaches generateProjectDocs.
- Wrap the output path construction with path.resolve and verify the resolved path starts with the intended base directory; reject otherwise.
- Sandbox the MCP process using OS-level controls (containers, chroot, AppArmor, or SELinux) to contain filesystem access.
- Disable or remove the analyze-project tool exposure until upstream input validation is added.
# Configuration example: run the MCP server as a restricted user in a scoped directory
useradd -r -s /usr/sbin/nologin mcp-analyzer
mkdir -p /srv/mcp/projects /srv/mcp/docs
chown -R mcp-analyzer:mcp-analyzer /srv/mcp
chmod 750 /srv/mcp
sudo -u mcp-analyzer node /opt/react-analyzer-mcp/dist/index.js \
--projects-dir /srv/mcp/projects \
--docs-dir /srv/mcp/docs
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
