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CVE-2026-45398

Openwebui Open Webui broken access control

7.5 HIGHPublic exploitEPSS 0.49%
  1. Published15 May 2026

Description

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.5, _validate_collection_access() 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. This vulnerability is fixed in 0.9.5.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityHigh
Privileges requiredLow
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

Openwebui Open Webui< 0.9.5

Remediation

Fixed in
Openwebui Open Webui≥ 0.9.5

References

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Frequently asked

Is CVE-2026-45398 being actively exploited?

CVE-2026-45398 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.49%.

How severe is CVE-2026-45398?

CVE-2026-45398 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 0.49% probability of exploitation.

Which products are affected by CVE-2026-45398?

Affected products include Openwebui Open Webui.

How do I fix CVE-2026-45398?

Upgrade affected software to a fixed version, for example Openwebui Open Webui 0.9.5 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-45398 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.