GHSA-3xpf-xq7r-v8c5 is a high-severity (CVSS 8.2) Cross-site Scripting (XSS) vulnerability in open-webui. A fix is available for open-webui — see the affected versions and patch details below.
Open WebUI: Same-origin XSS to account takeover via terminal file-preview iframe hardcoding allow-same-origin
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-3xpf-xq7r-v8c5.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-3xpf-xq7r-v8c5 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
open-webuiReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Summary
Any authenticated user with access to a terminal server could get script of their choosing to run in the Open WebUI origin itself. The HTML file preview rendered terminal-served files in an iframe whose sandbox always granted allow-same-origin alongside allow-scripts, and the file is served from a path on the application's own origin, so the sandbox provided no isolation at all. Script in a previewed file could read the victim's session token and take over the account.
Preconditions
- At least one terminal server configured by an admin (
TERMINAL_SERVER_CONNECTIONS, empty by default) and reachable by the victim. Deployments with no terminal server configured are not affected. - The attacker needs a normal authenticated account with access to that terminal server, no admin rights.
- No victim interaction beyond having the chat open: a
display_filetool call opens the preview automatically. TERMINAL_PROXY_HEADERSunset, which is the default. An operator who had already set a restrictive Content-Security-Policy through it was not exposed, since those headers are merged into every proxied response including the served file.- The
iframeSandboxAllowSameOriginuser setting is off by default, but the affected branch ignored it entirely.
Impact
The previewed document runs in the application origin, so it can reach the parent window, read the session token out of localStorage and exfiltrate it, which is full account takeover of the victim. If the victim is an admin, or any user holding workspace.functions, that takeover extends to server-side code execution through Functions. Getting the malicious file written and displayed still requires a prompt-injection or a social step, which is what keeps the complexity high rather than trivial. Instances with no terminal server configured were never affected, and neither was the srcdoc preview path.
Fix
Fixed in 0.11.0 by 65a5fad7b (#26907). The serveUrl preview branch now gates allow-same-origin behind the same iframeSandboxAllowSameOrigin setting the srcdoc branch already used, so by default the preview loads at an opaque origin and cannot reach the parent context. Upgrading is sufficient, no configuration change is required, and HTML previews continue to render normally.
Root cause
src/lib/components/chat/FileNav/FilePreview.svelte, theserveUrliframe branch, reached for HTML files served through/api/v1/terminals/{id}/files/serve/....- Present from 0.9.0, where that branch was introduced, through 0.10.2.
The component grew two preview paths. The srcdoc path was hardened: same-origin became opt-in and a CSP was injected into the document. The serveUrl path, added later for files streamed from a terminal server, kept a static sandbox string with allow-same-origin baked into it. Because the terminal proxy is mounted under the application's own origin and forwards the upstream response without adding a Content-Security-Policy of its own unless the operator configured one, and no global CSP is set, the sandbox was the only isolation boundary left, and it was granting precisely the permission that dissolved it.
Proof of concept
Write an HTML file containing a script that reads window.parent.localStorage.token to a terminal server the victim can reach, then trigger display_file for that file. The chat handler opens the preview on the resulting terminal:display_file event with no click, the script executes at the application origin, and the token is exfiltrated.
Credits
Reported by @manus-use (researcher zx / Jace).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | open-webui | ≥ 0.9.0&&< 0.11.0 | 0.11.0pip install --upgrade 'open-webui==0.11.0' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for open-webui, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update open-webui to 0.11.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3xpf-xq7r-v8c5 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-3xpf-xq7r-v8c5 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-3xpf-xq7r-v8c5. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-3xpf-xq7r-v8c5 in your dependencies?
O3 Security finds GHSA-3xpf-xq7r-v8c5 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.