OpenClaw: Gateway WebSocket Denial of Service via unbounded pre-auth upgrades

Summary

The gateway accepted unbounded concurrent unauthenticated WebSocket upgrades before allocating them to an authenticated session budget.

Impact

An unauthenticated network attacker could consume socket and worker capacity and disrupt WebSocket availability for legitimate clients.

Affected Component

src/gateway/server-http.ts, src/gateway/server/preauth-connection-budget.ts

Fixed Versions

• Affected: <= 2026.3.24
• Patched: >= 2026.3.28
• Latest stable 2026.3.28 contains the fix.

Fix

Fixed by commit cb5f7e201f (gateway: cap concurrent pre-auth websocket upgrades).

Discovered by：Topsec AlphaLab (wang dong)