Vulnerability in Open-Webui
CVE-2026-45396
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.5, the POST /api/v1/evaluations/feedback endpoint in Open WebUI v0.9.2 is vulnerable to mass assignment via FeedbackForm, which uses model_config = ConfigDict(extra='allow'). Due to an insecure dictionary merge order in insert_new_feedback(), an authenticated attacker can inject a user_id field in the request body that overwrites the server-derived value, creating feedback records attributed to any arbitrary user. This corrupts the model evaluation leaderboard (Elo ratings) and enables identity spoofing. This vulnerability is fixed in 0.9.5.
Vulnerability class: Mass Assignment
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L.
EPSS exploit prediction
EPSS: 0.004 (26.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 27th percentile — 26.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001
Affected products
- Open-Webui — versions < 0.9.5
- Openwebui Open Webui
Weakness classification (CWE)
References
- github.com/open-webui/open-webui/security/advisories/GHSA-rjmp-vjf2-qf4g (Exploit, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-45396?
- CVE-2026-45396 is a medium-severity vulnerability in Open-Webui, classified under Improperly Controlled Modification of Dynamically-Determined Object Attributes. CVSS score: 5.4/10. Published 2026-05-15.
- How severe is CVE-2026-45396?
- Medium severity. CVSS v3 base score is 5.4 out of 10.