What’s Vulnerable › Vulnerabilities

CVE-2026-45396: Open WebUI: Mass Assignment via FeedbackForm extra=allow Allows Feedback User ID Spoofing and Evaluation Data Manipulation

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-05-15 · updated 2026-06-17
• Weakness: CWE-915

Description

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.

Affected products

• open-webui: before 0.9.5 — fixed in 0.9.5

How to fix

Upgrade to a fixed version: open-webui 0.9.5. Check the vendor advisory for mitigations.

References

• https://github.com/open-webui/open-webui/security/advisories/GHSA-rjmp-vjf2-qf4g
• https://github.com/open-webui/open-webui/security/advisories/GHSA-rjmp-vjf2-qf4g

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