Security vulnerabilities and automated fixes for file upload issues
6 posts found
The review image upload handler in this Deno-based app trusted the client-supplied filename extension to decide whether a file was a "safe" image, without ever inspecting the actual file bytes. The fix adds magic-byte signature verification for PNG, JPEG, GIF, and WEBP formats before the file is written to disk, closing the door on disguised executables and malicious payloads.
A critical file type validation vulnerability in `src/js/insert.js` allowed attackers to rename malicious executables with image extensions and bypass security checks. The fix implements magic byte verification to confirm actual file content matches the declared file type, preventing attackers from disguising dangerous files as harmless images.
A critical vulnerability in the file upload handler allowed attackers to inject CRLF sequences into HTTP response headers through crafted filenames. The fix sanitizes user-supplied filenames before using them in Content-Disposition headers, preventing header injection attacks that could lead to cache poisoning, session fixation, or XSS.
A medium-severity vulnerability in a file transfer receiver allowed attackers to exhaust server resources by sending maliciously crafted import files with no size limits, no JSON depth restrictions, and millions of entries loaded directly into memory. The fix introduces explicit input validation guards that reject unauthenticated or malformed requests before any disk or network operations begin. Understanding this class of vulnerability is essential for any developer building file ingestion pipe
A critical security vulnerability was discovered and patched in a Flask REST API endpoint that accepted image file uploads without any validation, size limits, or sandboxing. An attacker could exploit this flaw to upload malicious files disguised as images, potentially leading to remote code execution or exploitation of image-parsing libraries. The fix enforces strict file type validation, magic byte inspection, and upload size limits to close this dangerous attack vector.
A medium-severity vulnerability in file import functionality left applications vulnerable to Denial of Service (DoS) attacks through maliciously crafted files. By exploiting missing resource limits and validation checks, attackers could exhaust server memory with deeply nested JSON or oversized files, potentially bringing down entire services.