CVE-2026-87996: Open WebUI: SSRF into internal services via DNS rebinding in the Playwright web loader

With the Playwright web loader enabled, Open WebUI checks the address behind a user-submitted URL before allowing the request, then handed the request to the browser to perform. The browser resolved the hostname a second time, on its own, and that answer was never checked. An attacker who controls the authoritative DNS for a hostname they submit can answer the first lookup with a public address and the second with an internal one, so the browser connects to an address the check exists to block. The connection-layer pinning that protects the other fetch paths could not apply here, because the request ran inside the browser rather than through our own HTTP clients.