Express XSS Sanitizer is Express 4.x and 5.x middleware which sanitizes user input data (in req.body, req.query, req.headers and req.params) to prevent Cross Site Scripting (XSS) attack.
CVSS 3.1HIGH 8.2·Network·No auth·No interaction·EPSS 0.00389·Published 2026-03-27·Fixed in 2.0.2CWE-183
The package express-xss-sanitizer before 1.1.3 are vulnerable to Prototype Pollution via the allowedTags attribute, allowing the attacker to bypass xss sanitization.
CVSS 3.1HIGH 7.3·Network·No auth·No interaction·EPSS 0.00954·Published 2022-09-26·Fixed in 1.1.3CWE-1321
The express-xss-sanitizer (aka Express XSS Sanitizer) package through 2.0.0 for Node.js has an unbounded recursion depth in sanitize in lib/sanitize.js for a JSON request body.
CVSS 3.1MEDIUM 5.3·Network·No auth·No interaction·EPSS 0.00449·Published 2025-09-14·Fixed in 2.0.1CWE-674