Summary
Open WebUI vulnerable to Stored XSS via iFrame in citations model
Full technical description
Manually modifying chat history allows setting the html property within document metadata. This causes the frontend to enter a code path that treats document contents as HTML, and render them in an iFrame when the citation is previewed. This allows stored XSS via a weaponised document payload in a chat. The payload also executes when the citation is viewed on a shared chat.
Details
The vulnerability stems from how iFrame are implemented here:
https://github.com/open-webui/open-webui/blob/6f1486ffd0cb288d0e21f41845361924e0d742b3/src/lib/components/chat/Messages/Citations/CitationModal.svelte#L163-L170
The html attribute can be controlled by a user who manually edits the chat history. Since allow-scripts and allow-same-origin are harcoded here the sandboxing offers essentially no protection.
PoC
Create an arbitrary chat with a file upload attached:
Edit the response
Before saving, configure the browser to use an HTTP proxy tool (Burp/Caido/ZAP) and intercept the save request. Find the object within the history and then messages objects (not the messages array) that contains the document source.
Add html: true to metadata, update the document to an XSS payload, and forward the request.
Observe the payload is rendered in the iFrame and the javascript executes.
The payload also executes when viewed from a shared version of the chat.
Caveats
The victim must expand the sources and click the document containing the payload to trigger this issue.
Impact
Any user can create a weaponised chat that can be shared and subsequently used to target other users.
Low privilege users are at risk of having their session taken over by a payload that reads their token from local storage and exfiltrates it to an attacker controlled server.
Admins are at risk of exposing the server to RCE via same chain described in https://github.com/advisories/GHSA-w7xj-8fx7-wfch.
Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.
CVE-2026-26192 has a CVSS score of 7.3 (High). The vector is network-reachable, low privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.7.0); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2026-26192? CVE-2026-26192 is a high-severity cross-site scripting (XSS) vulnerability in open-webui (pip), affecting versions < 0.7.0. It is fixed in 0.7.0. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
- How severe is CVE-2026-26192? CVE-2026-26192 has a CVSS score of 7.3 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of open-webui are affected by CVE-2026-26192? open-webui (pip) versions < 0.7.0 is affected.
- Is there a fix for CVE-2026-26192? Yes. CVE-2026-26192 is fixed in 0.7.0. Upgrade to this version or later.
- Is CVE-2026-26192 exploitable, and should I be worried? Whether CVE-2026-26192 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-26192 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-26192? Upgrade
open-webuito 0.7.0 or later.