CVE-2026-45386: Open WebUI: An IDOR vulnerability exists in the pin_channel_message API endpoint

Severity: medium (CVSS 4.3 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-639

Description

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.5, Pin/Unpin is a write operation (modifies the message's is_pinned , pinned_by, pinned_at fields), but in standard channels it only checks read permission, allowing users with read-only access to pin/unpin any message. 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-5gc6-xhv4-2wg6
https://github.com/open-webui/open-webui/security/advisories/GHSA-5gc6-xhv4-2wg6

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