Open WebUI: RAG ACL Bypass in Milvus Multitenancy Mode

Exploitation

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

CVSS

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

EPSS

• CVE-2026-54019: 0.39% estimated exploitation activity in the next 30 days; percentile 32.68 (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.

RAG ACL Bypass in Milvus Multitenancy Mode Summary This is a bypass of the fix for: - GHSA-h36f-rqpx-j5wx - CVE-2026-44560 - "Unauthorized File and Knowledge Base Content Access via RAG Vector Search" Open WebUI added collection-level ACL checks, but the patch can still be bypassed when Milvus multitenancy mode is enabled. The ACL allows unknown non-KB collection names as legacy/ephemeral collections. In Milvus multitenancy mode, that user-controlled collection name becomes a resourceid and is interpolated into a Milvus expression without escaping. An authenticated non-admin user can query: This passes the Open WebUI ACL as an unknown collection, but Milvus evaluates: That returns private knowledge-base chunks belonging to other users. Affected Configuration Tested on: This is not a default-vector-store issue. It affects production deployments using Milvus multitenancy. Impact An authenticated low-privilege user can read private RAG / knowledge-base content they do not have access…

Published by the source

17 Jun 2026, 17:57 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-p5cp-r7rg-qpxc

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-p5cp-r7rg-qpxc

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# Patch Next advisory brief: CVE-2026-54019

Advisory: Open WebUI: RAG ACL Bypass in Milvus Multitenancy Mode
IDs: CVE-2026-54019, GHSA-p5cp-r7rg-qpxc
Record: https://patchnext.com/advisories/cve-2026-54019 (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 6.5)
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-p5cp-r7rg-qpxc (OSV record GHSA-p5cp-r7rg-qpxc lists affected ranges: PyPI open-webui >=0 <0.9.6 (fixed))
- Verified: https://github.com/advisories/GHSA-p5cp-r7rg-qpxc (GitHub-reviewed advisory GHSA-p5cp-r7rg-qpxc lists affected ranges: PyPI open-webui >=0 <=0.9.5)

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