Open WebUI: Any authenticated user can suppress calendar alerts instance-wide via a non-numeric alert value

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:N/A:L

EPSS

• CVE-2026-87012: 0.48% estimated exploitation activity in the next 30 days; percentile 41.78 (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.

Any authenticated user can suppress calendar alerts instance-wide via a non-numeric alert value Summary Calendar events carry a free-form meta object that is stored exactly as submitted, with no validation of the values inside it. The scheduler reads the per-event alert offset out of that object in a single pass that covers every user's upcoming events, and compares it numerically without checking that it is a number. Any verified user could store a text value there, which made the comparison raise and abort the whole pass, so no calendar reminder fired for anyone on the instance while that event stayed inside the lookahead window. Preconditions - Calendar is enabled (ENABLECALENDAR / calendar.enable, default True). - The attacker is a verified user (role user or admin) holding the calendar feature permission, which is granted to all users by default (USERPERMISSIONSFEATURESCALENDAR, default True). - The event's start time falls inside the scheduler's one hour lookahead window, so…

Published by the source

10 Sep 2026, 22:42 UTC

Last modified by the source

1 Oct 2026, 17:55 UTC

Source last checked

26 Oct 2026, 13:51 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-v39v-59xw-j98g

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-v39v-59xw-j98g

3. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-v39v-59xw-j98g

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# Patch Next advisory brief: CVE-2026-87012

Advisory: Open WebUI: Any authenticated user can suppress calendar alerts instance-wide via a non-numeric alert value
IDs: CVE-2026-87012, GHSA-v39v-59xw-j98g
Record: https://patchnext.com/advisories/cve-2026-87012 (revision 3, source checked 26 Oct 2026, 13:51 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 0.11.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI open-webui: affected >= 0.9.0, < 0.11.1; fixed in 0.11.1

## 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://github.com/advisories/GHSA-v39v-59xw-j98g (GitHub-reviewed advisory GHSA-v39v-59xw-j98g lists affected ranges: PyPI open-webui >=0.9.0 <0.11.1)
- Verified: https://osv.dev/vulnerability/GHSA-v39v-59xw-j98g (OSV record GHSA-v39v-59xw-j98g lists affected ranges: PyPI open-webui >=0.9.0 <0.11.1 (fixed))

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