How severe is CVE-2026-45398?

CVE-2026-45398 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-45398 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-45398?

CVE-2026-45398 affects Openwebui Open Webui. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-45398?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-45398 have an EU (EUVD) identifier?

Yes. CVE-2026-45398 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30634.

When was CVE-2026-45398 published?

CVE-2026-45398 was published on 2026-05-15 and last updated on 2026-06-17.

CVE-2026-45398

CVE-2026-45398 is a high-severity vulnerability in Openwebui Open Webui with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-639.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 0% (26th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-30634
Weakness: CWE-639
Affected product: Openwebui Open Webui
Published: 2026-05-15
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-45398?: 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.
How severe is CVE-2026-45398?: CVE-2026-45398 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-45398 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-45398?: CVE-2026-45398 affects Openwebui Open Webui. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-45398?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-45398 have an EU (EUVD) identifier?: Yes. CVE-2026-45398 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30634.
When was CVE-2026-45398 published?: CVE-2026-45398 was published on 2026-05-15 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:openwebui:open_webui:*:*:*:*:*:*:*:*

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