Medium 4.6Published Oct 12, 2026

CVE-2026-109300Open WebUI 0.6.31 before 0.11.4 Stored XSS via Tool-Call Embeds

Updated under an hour ago (2026-10-19 08:30 UTC)

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It affects open-webui. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for open-webui

Exploited in the last 30 days

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 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.

CVSS: 4.6 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N
Weakness (CWE): CWE-79
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: VulnCheck
NVD analysis: Awaiting Analysis
Record last updated: Oct 13, 2026
First seen by InfoSec Signals: Oct 12, 2026

Affected products

Affected products

open-webui open-webui open_webui:open_webui (from the name)	from 0.6.31 before 0.11.4; 0.11.4 not affected	CNA record

References

https://github.com/open-webui/open-webui/security/advisories/GHSA-9wj4-mcm3-ppj6vendor-advisory
https://www.vulncheck.com/advisories/open-webui-0.6.31-before-0.11.4-stored-xss-via-tool-call-embedsthird-party-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.