🎯 New Report #3972760: Open redirect on app.hey.com bypasses HEY desktop's internal-origin allowlist and loads attacker content inside a HEY BrowserWindow
🔺Severity: Medium
👽 Reporter: nasrysami
⭐️ Reputation: 185
🛠 State: resolved
💼 Team: Basecamp
💵 Bounty: null
🕐 Submitted: 2026-08-27
⏰ Disclosed: 2026-10-15 18:00:06
📝 Summary: A case-sensitive URL scheme comparison flaw in the proxy image endpoint allowed open redirects on the mail service's web domain. The endpoint failed to recognize uppercase HTTPS scheme variants and redirected users to unproxied URLs instead of properly proxying them. When combined with the desktop application's internal-origin allowlist, this flaw could be exploited to load attacker-controlled content within a desktop application window that lacked address bar indicators. The vulnerability was accessible without authentication and could be delivered through ordinary messages containing specially crafted links. A similar case-sensitive scheme comparison issue was identified in the inbound mail image rewriter, though no impact was demonstrated in that location. The flaw affected desktop versions on multiple platforms and was fixed through proper URL parsing and normalization of schemes before deciding whether to proxy requests.
📂 Report JSON File: 3972760
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