Capcut Bug Bounty Fix

ByteDance replaced numeric IDs with UUID v4 tokens and added server-side ownership validation. They paid a $4,000 bounty and pushed the fix in CapCut v8.5.0 within 18 days.

To eliminate BOLA/IDOR bugs, backend engineers move away from relying solely on client-side requests. Every API call requesting a resource must validate the user's session token against the specific resource owner in the database. SELECT * FROM projects WHERE id = :id capcut bug bounty fix

// Vulnerable: Loads any URL passed via the deep link intent Intent intent = getIntent(); Uri data = intent.getData(); String url = data.getQueryParameter("url"); myWebView.loadUrl(url); Use code with caution. The Fix: Strict Domain Whitelisting ByteDance replaced numeric IDs with UUID v4 tokens

Log out and log back in using only one method (e.g., just TikTok or just Google). Multiple simultaneous logins can trigger security alerts. Network Fixes Every API call requesting a resource must validate

When users import a project file or template, the application parses structure data (often JSON or XML). If the parser does not sanitize file paths, an attacker can craft a template that references local sensitive files (like session tokens or device databases) and forces the app to upload them. The Vulnerable Code (Conceptual Python/C++)

import os def load_project_asset_secure(asset_path): base_dir = os.path.abspath("/sdcard/capcut/projects/") # Resolve absolute target path, removing ".." target_path = os.path.abspath(os.path.join(base_dir, asset_path)) # Verify the target path stays inside the base directory if not target_path.startswith(base_dir + os.sep): raise PermissionError("Access Denied: Path Traversal Attempted.") with open(target_path, "rb") as f: return f.read() Use code with caution. Vulnerability B: Deep Link Hijacking / WebView XSS