vulnerability / NVI-00015087 / Revision 1
Open WebUI: Cross-origin postMessage confirmation bypass via action:submit
GitHub lists this reviewed advisory for open-webui. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
6.5 high
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
open-webui
source listed<= 0.9.5
### Summary The chat message listener allows non-same-origin `input:prompt` and `action:submit` messages, so an external site can set prompt text and trigger `submitPrompt()` in an authenticated victim session. I validated this with a cross-origin attacker page that auto-posted messages and caused unauthorized `POST /api/v1/chats/new` and `POST /api/chat/completions` requests containing attacker-controlled prompts. This enables cross-site forced actions and model/tool execution under victim privileges without consent. ### Details The chat page's window message listener in `src/lib/components/chat/Chat.svelte` processes message types including `input:prompt` and `action:submit` without adequately enforcing same-origin restrictions. Based on code around lines ~597-616, input text is set directly from `event.data.text`; `action:submit` proceeds to `submitPrompt()` on the current prompt. The logic does not apply a strict origin allowlist and permits non-same-origin control of the chat input and submission flow, leading to cross-origin command execution in the victim's authenticated UI context. As a result, backend API calls (e.g., `POST /api/v1/chats/new`, `POST /api/chat/completion
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-3vv5-8xxp-4f55 ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
Public revision history
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- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.