[GH-ISSUE #8998] More secure defaults: Disable CORS, and only bind to localhost #15351

New Issue

GiteaMirror · 2026-04-19T21:35:25-05:00

GiteaMirror commented

2026-04-19 21:35:25 -05:00

Originally created by @joliss on GitHub (Jan 27, 2025).
Original GitHub issue: https://github.com/open-webui/open-webui/issues/8998

CORS

If I understand the CORS warning below correctly, open-webui by default allows CORS requests from any origin. I might misunderstand and it actually has an additional security layer that stops misuse of this, but at first blush, this seems like something I definitely don't want, since it might allow any website that I'm opening in my browser to send CORS requests to localhost:8080 to download my chat history or run LLM requests.

$ open-webui serve --host localhost
Loading WEBUI_SECRET_KEY from file, not provided as an environment variable.
Loading WEBUI_SECRET_KEY from /Users/primary/.webui_secret_key
/opt/homebrew/lib/python3.11/site-packages/open_webui
/opt/homebrew/lib/python3.11/site-packages
/opt/homebrew/lib/python3.11
Running migrations
INFO  [alembic.runtime.migration] Context impl SQLiteImpl.
INFO  [alembic.runtime.migration] Will assume non-transactional DDL.
INFO  [open_webui.env] 'DEFAULT_LOCALE' loaded from the latest database entry
INFO  [open_webui.env] 'DEFAULT_PROMPT_SUGGESTIONS' loaded from the latest database entry
WARNI [open_webui.env]

WARNING: CORS_ALLOW_ORIGIN IS SET TO '*' - NOT RECOMMENDED FOR PRODUCTION DEPLOYMENTS.

INFO  [open_webui.env] Embedding model set: sentence-transformers/all-MiniLM-L6-v2
WARNI [langchain_community.utils.user_agent] USER_AGENT environment variable not set, consider setting it to identify your requests.

  ___                    __        __   _     _   _ ___
 / _ \ _ __   ___ _ __   \ \      / /__| |__ | | | |_ _|
| | | | '_ \ / _ \ '_ \   \ \ /\ / / _ \ '_ \| | | || |
| |_| | |_) |  __/ | | |   \ V  V /  __/ |_) | |_| || |
 \___/| .__/ \___|_| |_|    \_/\_/ \___|_.__/ \___/|___|
      |_|


v0.5.7 - building the best open-source AI user interface.

https://github.com/open-webui/open-webui

I figured out that CORS_ALLOW_ORIGIN=http://localhost open-webui serve probably disallows CORS from non-localhost origins. (I first tried CORS_ALLOW_ORIGIN= open-webui serve, but it crashed.)

Perhaps the UX and security could be improved by having CORS disallowed by default, and only allow it if CORS_ALLOW_ORIGIN is explicitly set. (For reference, CORS_ALLOW_ORIGIN seems to have been added in #4714, but it doesn't seem to have changed the default behavior to be more secure.)

Default bind

According to open-webui serve --help, the default host to bind to is 0.0.0.0, which allows anyone on the internet to connect to my server.

I would suggest that localhost is a more secure default. Anybody who wants their server to be reachable via any or all network interfaces can explicitly set --host to do so.

Note: I'm not familiar with how Docker manages incomes network connections and how this change might affect Docker. If we change this default, it might be worth checking

that it doesn't break the Docker image by making the server unreachable from outside of Docker, and
that the Docker image's configuration doesn't in turn re-export the server port to 0.0.0.0, but rather also uses localhost as a secure default.

Changing the default behavior for CORS and bind is probably a breaking change, so I would suggest bumping the major version (e.g. to 0.6.0) with this change.

Originally created by @joliss on GitHub (Jan 27, 2025). Original GitHub issue: https://github.com/open-webui/open-webui/issues/8998 ## CORS If I understand the CORS warning below correctly, open-webui by default allows CORS requests from any origin. I might misunderstand and it actually has an additional security layer that stops misuse of this, but at first blush, this seems like something I definitely don't want, since it might allow any website that I'm opening in my browser to send CORS requests to localhost:8080 to download my chat history or run LLM requests. ``` $ open-webui serve --host localhost Loading WEBUI_SECRET_KEY from file, not provided as an environment variable. Loading WEBUI_SECRET_KEY from /Users/primary/.webui_secret_key /opt/homebrew/lib/python3.11/site-packages/open_webui /opt/homebrew/lib/python3.11/site-packages /opt/homebrew/lib/python3.11 Running migrations INFO [alembic.runtime.migration] Context impl SQLiteImpl. INFO [alembic.runtime.migration] Will assume non-transactional DDL. INFO [open_webui.env] 'DEFAULT_LOCALE' loaded from the latest database entry INFO [open_webui.env] 'DEFAULT_PROMPT_SUGGESTIONS' loaded from the latest database entry WARNI [open_webui.env] WARNING: CORS_ALLOW_ORIGIN IS SET TO '*' - NOT RECOMMENDED FOR PRODUCTION DEPLOYMENTS. INFO [open_webui.env] Embedding model set: sentence-transformers/all-MiniLM-L6-v2 WARNI [langchain_community.utils.user_agent] USER_AGENT environment variable not set, consider setting it to identify your requests. ___ __ __ _ _ _ ___ / _ \ _ __ ___ _ __ \ \ / /__| |__ | | | |_ _| | | | | '_ \ / _ \ '_ \ \ \ /\ / / _ \ '_ \| | | || | | |_| | |_) | __/ | | | \ V V / __/ |_) | |_| || | \___/| .__/ \___|_| |_| \_/\_/ \___|_.__/ \___/|___| |_| v0.5.7 - building the best open-source AI user interface. https://github.com/open-webui/open-webui ``` I figured out that `CORS_ALLOW_ORIGIN=http://localhost open-webui serve` probably disallows CORS from non-localhost origins. (I first tried `CORS_ALLOW_ORIGIN= open-webui serve`, but it crashed.) Perhaps the UX and security could be improved by having CORS disallowed by default, and only allow it if CORS_ALLOW_ORIGIN is explicitly set. (For reference, CORS_ALLOW_ORIGIN seems to have been added in #4714, but it doesn't seem to have changed the default behavior to be more secure.) ## Default bind According to `open-webui serve --help`, the default host to bind to is `0.0.0.0`, which allows anyone on the internet to connect to my server. I would suggest that `localhost` is a more secure default. Anybody who wants their server to be reachable via any or all network interfaces can explicitly set `--host` to do so. Note: I'm not familiar with how Docker manages incomes network connections and how this change might affect Docker. If we change this default, it might be worth checking * that it doesn't break the Docker image by making the server unreachable from outside of Docker, and * that the Docker image's configuration doesn't in turn re-export the server port to `0.0.0.0`, but rather also uses `localhost` as a secure default. -------------- Changing the default behavior for CORS and bind is probably a breaking change, so I would suggest bumping the major version (e.g. to 0.6.0) with this change.

GiteaMirror closed this issue

2026-04-19 21:35:26 -05:00

Sign in to join this conversation.

Branches Tags

1 Participants

Notifications

Due Date

No due date set.

Dependencies

No dependencies set.

Reference: github-starred/open-webui#15351