{"id":"CVE-2026-109300","title":"Open WebUI from 0.6.31 before 0.11.4 contains a stored cross-site scripting vulnerability in its Markdown renderer, which treats user-authored tool-call details blocks as tool output and mounts their embeds attribute in script-enabled if…","summary":"Open WebUI from 0.6.31 before 0.11.4 contains a stored cross-site scripting vulnerability in its Markdown renderer, which treats user-authored tool-call details blocks as tool output and mounts their embeds attribute in script-enabled if…","severity":"medium","cvss":4.6,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N","cwe":["CWE-79"],"published":"2026-10-12","updated":"2026-10-12","sourceUpdated":"2026-10-12T17:17:23.700","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-109300","references":[{"url":"https://github.com/open-webui/open-webui/security/advisories/GHSA-9wj4-mcm3-ppj6","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/open-webui-0.6.31-before-0.11.4-stored-xss-via-tool-call-embeds","label":"disclosure@vulncheck.com"}],"tags":["nvd"],"ingestedAt":"2026-10-12T18:00:08.194Z","slug":"CVE-2026-109300","body":"## Overview\n\nOpen WebUI from 0.6.31 before 0.11.4 contains a stored cross-site scripting vulnerability in its Markdown renderer, which treats user-authored tool-call details blocks as tool output and mounts their embeds attribute in script-enabled iframes. Authenticated users can post crafted channel messages, chat messages, or citation content that runs JavaScript in viewers' browsers, enabling in-app phishing, or session hijacking where iframeSandboxAllowSameOrigin is enabled.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":25,"depthScoreParts":{"impact":25.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}