GHSA-cqp4-qqvg-3787
HIGHGHSA-cqp4-qqvg-3787 is a high-severity (CVSS 8.1) Cross-site Scripting (XSS) vulnerability in open-webui. O3 Security confirms whether GHSA-cqp4-qqvg-3787 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Open WebUI has Stored XSS in Banner Component via Improper Sanitization Order
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for GHSA-cqp4-qqvg-3787.
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-cqp4-qqvg-3787 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 358,265 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
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
open-webuinpmDescription
Summary
A Stored Cross-Site Scripting (XSS) vulnerability exists in the Banner component due to an improper sanitization order (specifically, DOMPurify is executed before the marked library).
This vulnerability allows a compromised or malicious administrator to plant a malicious payload in the global banner. Crucially, this vector enables Privilege Escalation, as the malicious banner is rendered for all users, including the Super Admin (Primary Admin).
Consequently, the payload successfully bypasses the existing security mechanism. An attacker can leverage this to steal the Super Admin's session token
Details
Root Cause: The code attempts to sanitize the input using DOMPurify.sanitize() before parsing it with marked.parse().
DOMPurify cleans the raw input. Since Link is valid text (not HTML), it passes through DOMPurify unchanged. marked handles the text and converts it into a clickable HTML link: <a href="javascript:alert(javascript:alert(localStorage.token))">Link</a>. This resulting unsafe HTML is rendered directly via {@html ...} without further checks.
src/lib/components/common/Banner.svelte (Line 103)
{@html marked.parse(DOMPurify.sanitize((banner?.content ?? '').replace(/\n/g, '<br>')))}
POC
- Attacker Action: Log in as a compromised Admin account and navigate to Settings > Interface > UI > Banners.
- Injection: Add a new banner and enter the following payload in the content field. This payload creates a link that alerts the user's session token when clicked.
[Click for Security Update](javascript:alert(localStorage.token)) - Execution: Click Save. The malicious banner is now stored and active.
- Victim Action (Privilege Escalation): The Primary Admin logs in and sees the banner on the main dashboard. Believing it to be a system notification, they click the link. Victim Dashboard View:
- Result: The JavaScript executes immediately within the Primary Admin's session, exposing their full-access token.
Impact
Extend permissions and damage to the entire system. You need administrator privileges to create banners, but this vulnerability is important because it can attack primary administrators and other administrators.
Destination: Other Administrators /Primary Administrators. Attack Vector: Corrupting all administrator accounts (even those with limited scope if future granular privileges exist or simply credentials are compromised) could allow an attacker to set traps for the default administrator. The result: Unlike self-XSS or simple administrator configuration changes, this allows you to capture active sessions for the most privileged users and bypass authentication controls such as MFA (because the session is already active).
Recommended Patch
Modify src/lib/components/common/Banner.svelte (Line 103):
{@html DOMPurify.sanitize(marked.parse((banner?.content ?? '').replace(/\n/g, '<br>')))}
Resolution
Fixed in v0.8.0. src/lib/components/common/Banner.svelte:103 now applies the sanitization in the correct order: DOMPurify.sanitize(marked.parse(...)). marked.parse runs first and converts [text](javascript:...) markdown into the corresponding HTML link element; DOMPurify.sanitize then strips the javascript: URL and any other dangerous attributes/elements before the result reaches {@html ...}.
Users on >= 0.8.0 are not affected.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | open-webui | all versions | 0.8.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for open-webui. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update open-webui to 0.8.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-cqp4-qqvg-3787 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 pinpoints whether GHSA-cqp4-qqvg-3787 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-cqp4-qqvg-3787. 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-cqp4-qqvg-3787 in your dependencies?
O3 detects GHSA-cqp4-qqvg-3787 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.