Open WebUI Vulnerable to IDOR: Retrieval API Bypasses Knowledge Base Access Controls

Exploitation

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

CVSS

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

EPSS

• CVE-2026-45398: 0.33% estimated exploitation activity in the next 30 days; percentile 26.27 (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.

IDOR: Retrieval API Bypasses Knowledge Base Access Controls Author: Andrew Orr <aorr@tenable.com Summary validatecollectionaccess() (PR #22109) checks the user-memory- and file- collection name prefixes but does not check knowledge base collections, which use raw UUIDs as collection names. Any authenticated user who knows a private knowledge base UUID can read its content through the retrieval query endpoints, even though the knowledge API correctly denies that user access. The same gap affects the retrieval write endpoints (/process/text, /process/file, /process/files/batch, /process/web, /process/youtube), allowing an attacker to inject content into or overwrite another user's knowledge base. Reproduced on main at commit 4d058a125 (v0.8.11) on March 26, 2026. Severity - CWE-639: Authorization Bypass Through User-Controlled Key - CVSS 3.1: 7.5 (AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H) -- AC:H because exploitation requires knowing a target UUID; I:H and A:H because the write path allows…

Published by the source

14 May 2026, 20:26 UTC

Last modified by the source

13 Jul 2026, 16:43 UTC

Source last checked

26 Oct 2026, 13:41 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-4g37-7p2c-38r9

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-4g37-7p2c-38r9

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# Patch Next advisory brief: CVE-2026-45398

Advisory: Open WebUI Vulnerable to IDOR: Retrieval API Bypasses Knowledge Base Access Controls
IDs: CVE-2026-45398, GHSA-4g37-7p2c-38r9
Record: https://patchnext.com/advisories/cve-2026-45398 (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 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: open-webui 0.9.5. 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-4g37-7p2c-38r9 (OSV record GHSA-4g37-7p2c-38r9 lists affected ranges: PyPI open-webui >=0 <0.9.5 (fixed))
- Verified: https://github.com/advisories/GHSA-4g37-7p2c-38r9 (GitHub-reviewed advisory GHSA-4g37-7p2c-38r9 lists affected ranges: PyPI open-webui >=0 <=0.9.4)

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