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.

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Attack Requirements None

User Interaction Passive

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact Low

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact Low

Integrity Impact Low

Availability Impact None

User Interaction Required

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
open-webui open-webui unaffected
Version Status Constraints
0.6.31 affected < 0.11.4
0.11.4 unaffected —

No data.

No data.

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Project Subscriptions

Vendors Products
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Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/open-webui/open-webui/security/advisories/GHSA-9wj4-mcm3-ppj6 cve-icon cve-icon
https://www.vulncheck.com/advisories/open-webui-0.6.31-before-0.11.4-stored-xss-via-tool-call-embeds cve-icon cve-icon
History

Mon, 12 Oct 2026 16:30:00 +0000

Type Values Removed Values Added
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.
Title Open WebUI 0.6.31 before 0.11.4 Stored XSS via Tool-Call Embeds
First Time appeared Openwebui
Openwebui open Webui
Weaknesses CWE-79
CPEs cpe:2.3:a:openwebui:open_webui:*:*:*:*:*:*:*:*
Vendors & Products Openwebui
Openwebui open Webui
References
Metrics cvssV3_1

{'score': 4.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N'}

cvssV4_0

{'score': 5.1, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-10-12T16:04:58.200Z

Reserved: 2026-10-12T14:13:39.026Z

Link: CVE-2026-109300

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-12T17:17:23.700

Modified: 2026-10-12T17:17:23.700

Link: CVE-2026-109300

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-12T18:00:03Z

Weaknesses