CVE-2026-109287 open-webui CVE debrief

Who should care

Defenders responsible for Open WebUI deployments should assess exposure and prioritize remediation. This includes administrators, security teams, and developers working with Open WebUI.

Why it matters

CVE-2026-109287 is an information disclosure vulnerability in Open WebUI that allows users with read access to any knowledge base to potentially expose sensitive directory information. Defenders should prioritize verifying affected versions and applying patches or updates to prevent potential unauthorized access to knowledge base file listings and directory browsing.

• Potential exposure of sensitive directory information, including folder names, owner user IDs, and knowledge base IDs.
• Possible unauthorized access to knowledge base file listings and directory browsing.
• Need for verification of affected versions and application of patches or updates.
• Potential impact on confidentiality due to information disclosure.

Technical summary

The Open WebUI software contains an authorization flaw in its knowledge base file listing functionality. Specifically, the software does not verify that a supplied directory_id belongs to the requested knowledge base. This allows users with read access to any knowledge base to supply a retained foreign directory UUID to the GET /api/v1/knowledge/{id}/files endpoint. As a result, the returned breadcrumbs may expose folder names, owner user IDs, and knowledge base IDs of that directory and all its ancestors.

Defensive priority

Defenders should prioritize verifying the affected versions of Open WebUI in their environment and applying the necessary patches or updates.

Recommended defensive actions

• Verify the version of Open WebUI in use and compare it to the affected versions (0.9.6 through 0.11.3).
• Apply patches or updates to upgrade to a version of Open WebUI that is not affected (0.11.4 or later).
• Review and restrict access to the GET /api/v1/knowledge/{id}/files endpoint to prevent unauthorized directory ID usage.
• Monitor for any suspicious activity related to knowledge base file listings and directory browsing.
• Perform an inventory of assets using Open WebUI to identify potentially exposed systems.
• Develop a rollback plan in case issues arise during updates or patches.
• Track the status of remediation efforts and retest affected systems.

Evidence notes

The CVE record and source item provide details about the vulnerability, including its description, affected versions, and references to vendor advisories. Specifically, Open WebUI versions 0.9.6 through 0.11.3 are affected, and an attacker with read access to any knowledge base can exploit this issue by supplying a foreign directory UUID to the GET /api/v1/knowledge/{id}/files endpoint. Defenders should verify affected versions and apply patches or updates to prevent potential unauthorized access to knowledge base file listings and  b

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.