CVE-2026-109284

4.3Medium

Published 12 Oct 2026 · NVD status: Awaiting Analysis · AI triage by gemini-3.8-flash

4.3Medium

Attack vector: Network
Complexity: Low
Privileges needed: Low
User interaction: None
Impact: Limited impact
Weakness: CWE-862

Impact

Authenticated users downgraded to read-only access can insert unauthorized chats into shared folders. The attacker needs valid credentials and prior write access to the targeted folder.

Root cause

The chat fork endpoint places forked chats into the parent folder without verifying if the user currently holds write permissions.

Affected systems

Open WebUI 0.11.0 before 0.11.4

CVSS v3.1 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Fix & remediation

Upgrade Open WebUI to version 0.11.4 or later. If patching immediately is not possible, revoke folder access entirely for downgraded users rather than switching them to read-only.

shell

$ pip install --upgrade open-webui==0.11.4

AI-suggested. Run it in staging first and check it against the vendor advisory. Why?

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NVD 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.

References

Source: nvd.nist.gov/vuln/detail/CVE-2026-109284