How severe is CVE-2026-54021?

CVE-2026-54021 has a CVSS 3.x base score of 6.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2026-54021 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (11th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-54021?

CVE-2026-54021 affects Openwebui Open Webui. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-54021?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-54021 have an EU (EUVD) identifier?

Yes. CVE-2026-54021 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38522.

When was CVE-2026-54021 published?

CVE-2026-54021 was published on 2026-06-23 and last updated on 2026-06-26.

CVE-2026-54021

CVE-2026-54021 is a medium-severity vulnerability in Openwebui Open Webui with a CVSS 3.x base score of 6.3. 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-863.

Key facts

Severity: Medium (CVSS 3.x base score 6.3)
EPSS exploit prediction: 0% (11th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-38522
Weakness: CWE-863
Affected product: Openwebui Open Webui
Published: 2026-06-23
Last modified: 2026-06-26

Description

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.6, several direct, index-addressed Ollama proxy routes accept a caller-supplied url_idx path parameter and use it as a raw index into the admin-configured OLLAMA_BASE_URLS list. Access control on these routes validates only whether the user may use the requested model, never which backend the request is routed to. Any authenticated user can append an arbitrary url_idx to force their request onto an Ollama backend they were never authorized to reach, including internal, higher-privilege, or explicitly admin-disabled backends. This vulnerability is fixed in 0.9.6.

Frequently asked questions

What is CVE-2026-54021?: Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.6, several direct, index-addressed Ollama proxy routes accept a caller-supplied url_idx path parameter and use it as a raw index into the admin-configured OLLAMA_BASE_URLS list. Access control on these routes validates only whether the user may use the requested model, never which backend the request is routed to. Any authenticated user can append an arbitrary url_idx to force their request onto an Ollama backend they were never authorized to reach, including internal, higher-privilege, or explicitly admin-disabled backends. This vulnerability is fixed in 0.9.6.
How severe is CVE-2026-54021?: CVE-2026-54021 has a CVSS 3.x base score of 6.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2026-54021 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (11th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-54021?: CVE-2026-54021 affects Openwebui Open Webui. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-54021?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-54021 have an EU (EUVD) identifier?: Yes. CVE-2026-54021 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38522.
When was CVE-2026-54021 published?: CVE-2026-54021 was published on 2026-06-23 and last updated on 2026-06-26.

References

https://github.com/open-webui/open-webui/security/advisories/GHSA-9rpj-v7hf-vv2w

Affected products (1)

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

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