(0Day) Open WebUI Cleartext Transmission of Credentials Information Disclosure Vulnerability
Vulnerability Details
This vulnerability allows network-adjacent attackers to disclose sensitive information on affected installations of Open WebUI. Authentication is not required to exploit this vulnerability.
The specific flaw exists within the handling of credentials provided to the endpoint. The issue results from transmitting sensitive information in plaintext. An attacker can leverage this vulnerability to disclose transmitted credentials, leading to further compromise.
Additional Details
10/09/25 – ZDI submitted the report to the vendor’s GitHub account
10/10/25 – the vendor closed the report
10/15/25 – ZDI asked for the reason
11/10/25 – ZDI asked for the fix
12/10/25 – ZDI notified the vendor of the intention to publish the case as a 0-day advisory
UPDATE:
9/2/26 - The vendor states that further investigation showed that this describes the behavior of plain HTTP rather than a defect in the product. TLS termination is the operator's deployment decision, as it is for any backend that speaks HTTP.
https://docs.openwebui.com/security/vendor-dispositions/cve-2026-0767/
Disclosure Timeline
- 2025-10-09 - Vulnerability reported to vendor
- 2026-01-09 - Coordinated public release of advisory
- 2026-09-02 - Advisory Updated
Credit
Peter Girnus (@gothburz), Brandon Niemczyk of Trend Zero Day Initiative
