CVE-2026-109284

Medium

Description

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.

SeverityMedium

CVSS4.3

Exploit probability—

ProductOpen-webui

PublishedOct 12, 2026

First seenOct 12, 2026

Weakness typeCWE-862Missing authorization

How to fix

Update

open-webui open-webui0.11.4 or later

Vendor advisories

github.com/open-webui/open-webui/security/advisories/GHSA-6fjc-5cg3-mgvh

Affected products

Product	Affected versions	Fixed in
open-webui open-webui	0.11.0 ≤ v < 0.11.4	0.11.4

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