CVE-2026-27482: Ray dashboard DELETE endpoints allow unauthenticated browser-triggered DoS (Serve shutdown / job deletion)

Summary

Ray’s dashboard HTTP server blocks browser-origin POST/PUT but does not cover DELETE, and key DELETE endpoints are unauthenticated by default. If the dashboard/agent is reachable (e.g., --dashboard-host=0.0.0.0), a web page via DNS rebinding or same-network access can issue DELETE requests that shut down Serve or delete jobs without user interaction. This is a drive-by availability impact.

Details

• Middleware: python/ray/dashboard/http_server_head.py#get_browsers_no_post_put_middleware only checks POST/PUT via is_browser_request (UA/Origin/Sec-Fetch heuristics). DELETE is not gated.
• Endpoints lacking browser protection/auth by default:
• python/ray/dashboard/modules/serve/serve_head.py: @routes.delete("/api/serve/applications/") calls serve.shutdown().
• python/ray/dashboard/modules/job/job_head.py: @routes.delete("/api/jobs/{job_or_submission_id}").
• python/ray/dashboard/modules/job/job_agent.py: @routes.delete("/api/job_agent/jobs/{job_or_submission_id}") (not wrapped with deny_browser_requests either).
• Dashboard token auth is optional and off by default; binding to 0.0.0.0 is common for remote access.

PoC

Prereqs: dashboard reachable (e.g., ray start --head --dashboard-host=0.0.0.0), no token auth.

1. Start Serve (or have jobs present).
2. From any browser-reachable origin (DNS rebinding or same-LAN page), issue a DELETE fetch:

fetch("http://<dashboard-host>:8265/api/serve/applications/", {
    method: "DELETE",
    headers: { "User-Agent": "Mozilla/5.0" }  // browsers set this automatically
  });

Result: Serve shuts down.

1. Similarly, delete jobs:

fetch("http://<dashboard-host>:8265/api/jobs/<job_or_submission_id>", { method: "DELETE" }); fetch("http://<dashboard-agent>:52365/api/job_agent/jobs/<job_or_submission_id>", { method: "DELETE" });

Browsers will send the Mozilla UA and Origin/Sec-Fetch headers, but DELETE is not blocked by the middleware, so the requests succeed.

Impact

• Availability loss: Serve shutdown; job deletion. Triggerable via drive-by browser requests if the dashboard/agent ports are reachable and auth is disabled (default).
• No code execution from this vector, but breaks isolation/trust assumptions for “developer-only” endpoints.

Fix

The fix for this vulnerability is to update to Ray 2.54.0 or higher.

Fix PR: https://github.com/ray-project/ray/pull/60526