## CVE-2026-4867: High-Severity Vulnerability in path-to-regexp Library Threatens Express.js Applications
A high-severity vulnerability, CVE-2026-4867, has been detected in the widely used `path-to-regexp` npm library, version 0.1.7. This flaw, which generates a bad regular expression under specific conditions, poses a direct risk to the security and stability of any application that depends on it, particularly those built on the Express.js web framework. The vulnerable library is a core utility for Express-style path matching, making its presence in a dependency chain a critical point of exposure.

The vulnerability is embedded within `path-to-regexp-0.1.7.tgz`. It has been identified in the dependency hierarchy of `express-4.17.1.tgz`, where the vulnerable library is a direct dependency. This means countless Node.js projects using this common version of Express are potentially affected. The issue was found in the base `master` branch of a project, indicating it could be present in production deployments if not remediated. The specific impact involves the generation of a malformed regular expression, which can lead to application crashes or denial-of-service conditions, severely degrading service reliability.

This discovery triggers immediate scrutiny for development and security teams relying on the Express.js ecosystem. The `path-to-regexp` library is a fundamental building block for routing in many web applications, making this vulnerability a systemic risk. Organizations must audit their `package.json` files and `node_modules` directories to identify and upgrade the affected dependency. Failure to patch could leave web services vulnerable to instability and exploitation, emphasizing the ongoing challenge of securing software supply chains in open-source development.
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- **Source**: GitHub Issues
- **Sector**: The Lab
- **Tags**: CVE, npm, Express.js, Node.js, Supply Chain Security
- **Credibility**: unverified
- **Published**: 2026-03-28 01:27:01
- **ID**: 38614
- **URL**: https://whisperx.ai/en/intel/38614