Authorization bypass through user-controlled key in Open WebUI - CVE-2026-45402
Published: May 11, 2026
Vulnerability identifier: #VU130958
CSH Severity: Medium
CVSS v4: 8.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-45402
CWE-ID: CWE-639
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to disclose sensitive information.
The vulnerability exists due to authorization bypass through a user-controlled key in the folder knowledge ingestion and knowledge-base file attach endpoints when processing a user-supplied file_id without verifying access to the referenced file. A remote user can attach another user's file to a folder or knowledge base they control to disclose sensitive information.
Knowledge of the target file UUID is required, and the knowledge-base attach path can also enable modification of the attached file's content.
Affected software
Open WebUI
How to mitigate CVE-2026-45402
Install security update from vendor's website.
Open WebUI - update to 0.9.5