CVE-2026-87995

Open WebUI rendered terminal port content in an iframe sandbox that combined both allow-scripts and allow-same-origin, which provides no effective isolation because the terminal proxy serves that content from the Open WebUI origin itself. An authenticated user with access to a shared terminal server can host malicious script on a previewed port, and when another user opens that preview the script executes in the Open WebUI origin. The attacker's script can then hijack the victim's session and act on their behalf, yielding account takeover with high impact to confidentiality and integrity. All Open WebUI deployments running version 0.8.11 up to (but not including) 0.11.1 are affected, primarily multi-user instances where a terminal server is shared among users. No public proof of concept is known and the issue is not in CISA KEV, so there is no confirmed exploitation in the wild to date.

What to do: Upgrade to Open WebUI 0.11.1 or later, which removes the sandbox misconfiguration in the port preview. Until patched, restrict access to the shared terminal server to trusted users, discourage or disable the terminal port-preview feature for untrusted users, or serve terminal proxy content from a separate origin. Verify your currently deployed version and audit which accounts have access to the shared terminal server.