PatchSiren cyber security CVE debrief
CVE-2026-70480 open-webui CVE debrief
AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-08-04T20:16:54.903Z and has not been modified since then. Open WebUI, an extensible and feature-rich self-hosted AI platform, is vulnerable to a security issue. From version 0.6.34 until 0.11.0, Open WebUI renders vega and vega-lite fenced code blocks in chat content by building a Vega view in the viewer browser without a restricted resource loader. This allows any user who can place such a block where another user will see it to make that user's browser issue attacker-chosen outbound GET requests and read responses from same-origin or CORS-permissive targets into the rendered page. The issue is fixed in version 0.11.0. Users of Open WebUI, especially those with limited privileges, should be aware of this vulnerability and take necessary actions to mitigate it. System administrators and security teams responsible for Open WebUI installations should prioritize updating to version 0.11.0 or later.
- Vendor
- open-webui
- Product
- Unknown
- CVSS
- MEDIUM 4.1
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-08-04
- Original CVE updated
- 2026-08-05
- Advisory published
- 2026-08-04
- Advisory updated
- 2026-08-05
Who should care
Users of Open WebUI, especially those with limited privileges, should be aware of this vulnerability and take necessary actions to mitigate it. System administrators and security teams responsible for Open WebUI installations should prioritize updating to version 0.11.0 or later.
Technical summary
The Open WebUI platform, from version 0.6.34 until 0.11.0, is vulnerable to a security issue where users can make other users' browsers issue attacker-chosen outbound GET requests and read responses from same-origin or CORS-permissive targets. This is due to the rendering of vega and vega-lite fenced code blocks in chat content by building a Vega view in the viewer browser without a restricted resource loader. The issue has been fixed in version 0.11.0.
Defensive priority
Medium priority given the CVSS score of 4.1 and the potential for users with limited privileges to exploit the vulnerability.
Recommended defensive actions
- Review and update Open WebUI to version 0.11.0 or later to mitigate the vulnerability.
- Restrict the rendering of vega and vega-lite fenced code blocks in chat content.
- Implement a restricted resource loader for Vega views in the viewer browser.
- Monitor for suspicious outbound GET requests from users with limited privileges.
- Educate users on the potential risks of rendering untrusted content.
Evidence notes
The CVE-2026-70480 issue involves Open WebUI, an extensible, feature-rich, and user-friendly self-hosted AI platform. From version 0.6.34 until 0.11.0, Open WebUI renders vega and vega-lite fenced code blocks in chat content by building a Vega view in the viewer browser without a restricted resource loader. This allows any user who can place such a block where another user will see it to make that user's browser issue attacker-chosen outbound GET requests and read responses from same-origin or CORS-permissive targets into the rendered page. The issue is fixed in version 0.11.0.
Official resources
AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-08-04T20:16:54.903Z and has not been modified since then.