Advisory [CVE-2026-82438] Apache Storm: Description Three separate mechanisms allowed a web page on an unrelated origin to read responses that Storm's HTTP components served to an authenticated user

Three separate mechanisms allowed a web page on an unrelated origin to read responses that Storm's HTTP components served to an authenticated user.

The Logviewer reflected the request's `Origin` header back in `Access-Control-Allow-Origin` while also sending `Access-Control-Allow-Credentials: true`.

The published security model documents a permissive `Access-Control-Allow-Origin: *` posture as accepted, which is safe precisely because browsers refuse to

honour `*` together with credentials; reflecting the concrete origin removes that protection.

The shared CORS filter used by the UI, the Logviewer and DRPC was configured with a response header name where an initialisation parameter name was expected.

The container ignored the setting and applied its own defaults, which allow credentials.

Finally, the UI and Logviewer wrapped API responses in a caller-supplied JSONP callback for every GET A script element on any origin can load such a response, which bypasses the same-origin policy

entirely rather than negotiating it, and there was no way to turn the behaviour off.

In each case the effect is that a page visited by an authenticated operator can read cluster, topology log data on their behalf.

Affected product named by the advisory: Apache Storm.