Open WebUI IDOR: Calendar event re-parenting allows writing events into another user's calendar

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-2026-54006: 0.30% estimated exploitation activity in the next 30 days; percentile 22.68 (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 POST /api/v1/calendars/events/{eventid}/update validates that the caller has write access to the calendar the event currently belongs to, but does not validate the destination calendarid supplied in the request body. The model layer then persists the new calendarid unconditionally. A regular user-role account can therefore create an event in their own calendar and immediately move it into any other user's calendar whose ID they know — bypassing the authorization check that createevent correctly performs. This is reachable on default configuration: ENABLECALENDAR and USERPERMISSIONSFEATURESCALENDAR both default to True. Details Sink — missing destination check backend/openwebui/routers/calendar.py:283-297 backend/openwebui/models/calendar.py:658-693 (updateeventbyid) Reference — createevent does check the destination backend/openwebui/routers/calendar.py:255 Default-config gates (both True) - backend/openwebui/config.py:1658-1662 — ENABLECALENDAR defaults 'True' -…

Published by the source

17 Jun 2026, 14:09 UTC

Last modified by the source

20 Jul 2026, 21:15 UTC

Source last checked

26 Oct 2026, 13:49 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-f3g7-59qc-pqg6

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-f3g7-59qc-pqg6

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# Patch Next advisory brief: CVE-2026-54006

Advisory: Open WebUI IDOR: Calendar event re-parenting allows writing events into another user's calendar
IDs: CVE-2026-54006, GHSA-f3g7-59qc-pqg6
Record: https://patchnext.com/advisories/cve-2026-54006 (revision 2, source checked 26 Oct 2026, 13:49 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 0.9.6. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI open-webui: affected <= 0.9.5; fixed in 0.9.6

## 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-f3g7-59qc-pqg6 (OSV record GHSA-f3g7-59qc-pqg6 lists affected ranges: PyPI open-webui >=0 <0.9.6 (fixed))
- Verified: https://github.com/advisories/GHSA-f3g7-59qc-pqg6 (GitHub-reviewed advisory GHSA-f3g7-59qc-pqg6 lists affected ranges: PyPI open-webui >=0 <=0.9.5)

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