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Open WebUI: Mass Assignment via Pydantic extra='allow' Allows Creating Folders in Other Users' Accounts

Published May 15, 2026

Description

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, FolderForm uses model_config = ConfigDict(extra='allow'), which permits arbitrary fields to pass through Pydantic validation and be included in model_dump(exclude_unset=True). In insert_new_folder, the server-assigned user_id is placed at the start of the dict and then overwritten by the spread of form data. Because FolderModel declares user_id: str as a real field (not just a form extra), any attacker-supplied user_id in the POST body is accepted by the model and persisted on the Folder row. This vulnerability is fixed in 0.9.0.

Affected products

Remediation

No remediation recorded yet.

References (4)

Change history (0)

No recorded changes yet.

Sources
CVE.org / MITRE
Status PUBLISHED
Assigner GitHub_M
Published May 15, 2026
Updated May 15, 2026
Reserved May 6, 2026
CISA Vulnrichment
Updated May 15, 2026
NVD
Status Analyzed
Modified Jun 17, 2026
Red Hat
Severity n/a
Public date n/a
ENISA EUVD
Assigner GitHub_M
Published May 15, 2026
Updated May 15, 2026
Exploited since n/a
EUVD-2026-30603 GHSA-HR43-RJMR-7WMM