Open WebUI has an IDOR vulnerability in the pin_channel_message API endpoint

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

4.3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

EPSS

• CVE-2026-45386: 0.27% estimated exploitation activity in the next 30 days; percentile 19.68 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary Pin/Unpin is a write operation (modifies the message's ispinned , pinnedby, pinnedat fields), but in standard channels it only checks read permission, allowing users with read-only access to pin/unpin any message. Details https://github.com/open-webui/open-webui/blob/9bd84258d09eefe7bf975878fb0e31a5dadfe0f8/backend/openwebui/routers/channels.py#L1218 The channelhasaccess function https://github.com/open-webui/open-webui/blob/9bd84258d09eefe7bf975878fb0e31a5dadfe0f8/backend/openwebui/routers/channels.py#L75 checks user permissions against the AccessGrants table: The AccessGrant table distinguishes between read and write permission levels. PoC admin creates Standard Channel with Read-Only Access for test1 : admin posts a Message in the Channel, and test1 has read permission only. <img width="1024" height="423" alt="image" src="https://github.com/user-attachments/assets/e9912bd7-3908-44f2-8984-22d0535dc66f" / test1 attempts to Pin Message: Successfully pinned admin's message.…

Published by the source

14 May 2026, 20:25 UTC

Last modified by the source

13 Jul 2026, 16:42 UTC

Source last checked

26 Oct 2026, 13:41 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-5gc6-xhv4-2wg6

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-5gc6-xhv4-2wg6

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# Patch Next advisory brief: CVE-2026-45386

Advisory: Open WebUI has an IDOR vulnerability in the pin_channel_message API endpoint
IDs: CVE-2026-45386, GHSA-5gc6-xhv4-2wg6
Record: https://patchnext.com/advisories/cve-2026-45386 (revision 2, source checked 26 Oct 2026, 13:41 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 4.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: open-webui 0.9.5. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI open-webui: affected <= 0.9.4; fixed in 0.9.5

## Suggested inspection (read-only)
- `python -m pip show open-webui`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on open-webui.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-5gc6-xhv4-2wg6 (OSV record GHSA-5gc6-xhv4-2wg6 lists affected ranges: PyPI open-webui >=0 <0.9.5 (fixed))
- Verified: https://github.com/advisories/GHSA-5gc6-xhv4-2wg6 (GitHub-reviewed advisory GHSA-5gc6-xhv4-2wg6 lists affected ranges: PyPI open-webui >=0 <=0.9.4)

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