CVE-2026-45387: Open WebUI: Sharing models for others to use (read permission) also exposes model details (system prompt leakage)

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-05-15 · updated 2026-06-17
Weakness: CWE-200

Description

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.5, when setting model permissions so that a group has read access to it, intending for other users to use it, those users also can read the model's system prompt. However users may consider their system prompt confidential, so this is considered a security issue. 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

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