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TI-2026-71116 Aliases CVE-2026-109300GHSA-fc6p-2j86-rwxm

Stored cross-site scripting in Open WebUI via tool-call embeds

Priority MEDIUM 56CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Passive
Attack complexity
Low
Attack requirements
None
Impact type
Cross-site scripting
Confidentiality · integrity · availability
Low · Low · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-79.

Summary

Open WebUI from 0.6.31 before 0.11.4 contains a stored cross-site scripting flaw (CWE-79) in its Markdown renderer, which treats user-authored tool-call details blocks as tool output and mounts their embeds attribute in script-enabled iframes. An authenticated user can post crafted channel messages, chat messages or citation content that runs JavaScript in other users' browsers. This enables in-app phishing and, where iframeSandboxAllowSameOrigin is enabled, session hijacking.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00214 11th percentileScored 2026-11-07
Fix Fixed open-webui (open-webui): 0.11.4

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
open-webuiopen-webui0.6.31 to before 0.11.40.11.4Patch availableCNA
  • open-webui Vendoropen-webui Affected 0.6.31 to before 0.11.4 Fixed in 0.11.4 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:openwebui:open_webui:*:*:*:*:*:*:*:*——open-webui
  • cpe:2.3:a:openwebui:open_webui:*:*:*:*:*:*:*:* Versions — — ·open-webui

Remediation

Upgrade open-webui to version 0.11.4, which fixes the issue. The sources list no other fixed version for open-webui.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

  • Fix · CNA open-webui (open-webui) Fixed in 0.11.4

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    open-webui 0.11.4

    19 records Highest priority Priority HIGH 3 HIGH, 8 MEDIUM, 8 LOW

    Other records, highest priority first

    • TI-2026-71106 Stored cross-site scripting in Open WebUI via DOCX previewPriority HIGH 72
    • TI-2026-71108 Session cookie disclosure in Open WebUI OAuth-mode connectionsPriority HIGH 68
    • TI-2026-71104 Stored cross-site scripting in Open WebUI markdown linksPriority HIGH 67
    Show all 19 records →

Timeline

  1. 2026-10-12 Threatist record created from CVE-2026-109300
  2. 2026-10-12 Alias added: GHSA-fc6p-2j86-rwxm
  3. 2026-10-13 CISA SSVC decision points changed
  4. 2026-10-13 Priority changed: LOW → MEDIUM

References

Advisory 1

  • TI-2024-06216 Open WebUI Arbitrary File Upload + Path Traversal CVSS 3.1HIGH 8.8
  • TI-2024-07467 Improper Authentication in open-webui/open-webui CVSS 3.1HIGH 8.2
  • TI-2026-42359 Open WebUI: Cross-user code-interpreter and tool execution via unvalidated Socket.IO event-caller session_id CVSS 3.1CRITICAL 9.0
  • TI-2026-40759 open-webui - Remote Code Execution via CORS Misconfiguration and Session Validation CVSS 4.0CRITICAL 9.0
  • TI-2024-07431 Cross-site Scripting (XSS) in open-webui/open-webui CVSS 3.0CRITICAL 9.0
  • TI-2026-60021 Open WebUI: Same-origin XSS to account takeover via terminal port-preview iframe hardcoding allow-same-origin CVSS 3.1HIGH 8.7
See all 175 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences