Security vulnerabilities and automated fixes for multer issues
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A critical unrestricted file upload vulnerability was discovered in `mainsystem/routes/admin/profile.js`, where the avatar upload endpoint accepted any file type without validation. An authenticated attacker could upload a malicious server-side script to a web-accessible directory and execute arbitrary code on the server. The fix adds MIME type filtering, an allowlist of safe image formats, and a 2 MB file size limit to the multer middleware.
A high-severity Denial of Service vulnerability (CVE-2026-5079) was discovered in the multer package, a popular Node.js middleware for handling multipart form data. Attackers could craft malicious requests with deeply nested field names to exhaust server resources. The fix upgrades multer from version 2.0.2 to 2.2.0, which implements proper limits on field name parsing depth.