Vulnerability · Published Oct 12, 2026 · Assigned by VulnCheck

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

Medium 4.6

In plain English

A medium-severity cross-site scripting in open-webui from open-webui. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 12% of all known vulnerabilities).

Severity (CVSS 3.1)4.6Medium

Exploit odds (30 days)0.2%top 88.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
open-webui	open-webui	0.6.31 – before 0.11.4

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N

References

GitHub Security Advisory (GHSA-9wj4-mcm3-ppj6) vendor-advisory
VulnCheck Advisory: Open WebUI 0.6.31 before 0.11.4 Stored XSS via Tool-Call Embeds third-party-advisory