Advisories for Npm/Mcp-Sanitizer package

2026

mcp-sanitizer: URL sanitizer allows localhost/IPv6 loopback SSRF bypass via explicit port or bracketed IPv6

mcp-sanitizer v1.3.3 fails to block Server-Side Request Forgery (SSRF) targets when a localhost URL includes an explicit port (e.g., http://localhost:8080/) or when an IPv6 loopback/link-local address is expressed in bracketed notation (e.g., http://[::1]:8080/, http://[fe80::1]:8080/). Because the library is explicitly designed to gate MCP tool parameters such as web_fetch and web_scraper before outbound HTTP requests are made, a bypass here directly enables an attacker-controlled URL to reach internal services, leaking their …

mcp-sanitizer: File Path Sanitizer Permits Arbitrary User-Home Absolute Paths

mcp-sanitizer v1.3.3 explicitly whitelists /home/ and /Users/ as allowed absolute path prefixes in its file path validation logic (src/utils/validation-utils.js:188-196). As a result, paths such as /home/alice/.ssh/id_rsa and /home/alice/.aws/credentials pass through sanitizer.sanitize() with blocked=false, even though they point to highly sensitive files outside any configured safe root. Any consumer application that trusts the sanitized path and passes it to a filesystem read/write operation (e.g., fs.readFile) will expose arbitrary user-home directory files …