CVE-2026-54020: Open WebUI: DNS Rebinding SSRF Bypass

Open WebUI vetted user-supplied URLs by resolving the hostname once and rejecting private, loopback and link-local addresses, then let the HTTP client resolve that hostname again at connect time. An attacker who controls the authoritative DNS for a hostname they submit can answer with a public address during the check and an internal one at connect, so the fetch reaches an address the check was meant to block. Every user-reachable fetch gated by that check was affected, and most of them hand the internal response back to the attacker.