---
id: CVE-2026-109284
title: >-
  Open WebUI from 0.11.0 before 0.11.4 contains an improper authorization
  vulnerability in the chat fork handler, which places forked chats in the
  source chat's folder without checking folder write access
summary: >-
  Open WebUI from 0.11.0 before 0.11.4 contains an improper authorization
  vulnerability in the chat fork handler, which places forked chats in the
  source chat's folder without checking folder write access. Shared folder
  members downgraded …
severity: medium
cvss: 4.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N'
cwe:
  - CWE-862
published: '2026-10-12'
updated: '2026-10-12'
sourceUpdated: '2026-10-12T17:17:21.317'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-109284'
references:
  - url: >-
      https://github.com/open-webui/open-webui/security/advisories/GHSA-6fjc-5cg3-mgvh
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/open-webui-0.11.0-before-0.11.4-improper-authorization-via-chat-fork-endpoint
    label: disclosure@vulncheck.com
tags:
  - nvd
ingestedAt: '2026-10-12T18:00:08.188Z'
---

## Overview

Open WebUI from 0.11.0 before 0.11.4 contains an improper authorization vulnerability in the chat fork handler, which places forked chats in the source chat's folder without checking folder write access. Shared folder members downgraded to read-only can call POST /api/v1/chats/{id}/fork on chats they created there while they had write access, inserting attacker-controlled chats visible to the folder owner and members.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.