CVE-2026-54021
Open WebUI: Authenticated users can target arbitrary configured Ollama backends via unguarded url_idx path parameter
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.
INFO
Published Date :
June 23, 2026, 6:18 p.m.
Last Modified :
June 26, 2026, 8:17 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | MITRE-CVE | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update Open WebUI to version 0.9.6.
- Verify all Ollama backends are properly configured.
Public PoC/Exploit Available at Github
CVE-2026-54021 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-54021.
| URL | Resource |
|---|---|
| https://github.com/open-webui/open-webui/security/advisories/GHSA-9rpj-v7hf-vv2w | Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-54021 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-54021
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
None
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-54021 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-54021 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 26, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-54021', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-26T19:20:54.718364Z'} -
Initial Analysis by [email protected]
Jun. 25, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:openwebui:open_webui:*:*:*:*:*:*:*:* versions up to (excluding) 0.9.6 Added Reference Type GitHub, Inc.: https://github.com/open-webui/open-webui/security/advisories/GHSA-9rpj-v7hf-vv2w Types: Vendor Advisory -
New CVE Received by [email protected]
Jun. 23, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'open-webui', 'product': 'open-webui', 'versions': [{'status': 'affected', 'version': '< 0.9.6'}]}] Added 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. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L Added CWE CWE-863 Added Reference https://github.com/open-webui/open-webui/security/advisories/GHSA-9rpj-v7hf-vv2w