Open WebUI: Redis Cache Keys tool_servers and terminal_servers Missing Instance Prefix Enable Cross-Instance Cache Poisoning

Exploitation

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

CVSS

8.7 · CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N

EPSS

• CVE-2026-44552: 0.30% estimated exploitation activity in the next 30 days; percentile 23.37 (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.

Redis Cache Keys toolservers and terminalservers Missing Instance Prefix Enable Cross-Instance Cache Poisoning Affected Component Tool server and terminal server Redis cache: - backend/openwebui/utils/tools.py (line 841, toolservers SET) - backend/openwebui/utils/tools.py (line 850, toolservers GET) - backend/openwebui/utils/tools.py (line 976, terminalservers SET) - backend/openwebui/utils/tools.py (line 986, terminalservers GET) Affected Versions Current main branch (commit 6fdd19bf1) and likely all versions since the tool server / terminal server Redis cache was introduced. Description Open WebUI uses a REDISKEYPREFIX (default open-webui) to namespace Redis keys, allowing multiple instances to safely share a single Redis backend. Every Redis key in the codebase uses this prefix — except the toolservers and terminalservers keys in utils/tools.py, which use bare key names. When two or more Open WebUI instances share a Redis database (a supported and documented deployment pattern,…

Published by the source

8 May 2026, 19:44 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-3x8w-4f7p-xxc2

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-3x8w-4f7p-xxc2

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# Patch Next advisory brief: CVE-2026-44552

Advisory: Open WebUI: Redis Cache Keys tool_servers and terminal_servers Missing Instance Prefix Enable Cross-Instance Cache Poisoning
IDs: CVE-2026-44552, GHSA-3x8w-4f7p-xxc2
Record: https://patchnext.com/advisories/cve-2026-44552 (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: High (CVSS 8.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: open-webui 0.9.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI open-webui: affected <= 0.8.12; fixed in 0.9.0

## 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-3x8w-4f7p-xxc2 (OSV record GHSA-3x8w-4f7p-xxc2 lists affected ranges: PyPI open-webui >=0 <0.9.0 (fixed))
- Verified: https://github.com/advisories/GHSA-3x8w-4f7p-xxc2 (GitHub-reviewed advisory GHSA-3x8w-4f7p-xxc2 lists affected ranges: PyPI open-webui >=0 <=0.8.12)

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