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CVE-2026-44555— Open WebUI: Base Model Routing Bypasses Access Control via Model Chaining

Quick assessment

Affected
open-webui open-webui
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Open WebUI是Open WebUI开源的一个可扩展、功能丰富、用户友好的自托管 WebUI。 Open WebUI 0.9.0之前版本存在安全漏洞，该漏洞源于模型组合功能中，访问控制管道仅验证用户对组合模型的访问权限，但未重新验证对链式基础模型的访问权限，且模型创建和导入端点接受任意base_model_id值而不检查调用者是否有权访问该基础模型，导致任何具有默认模型创建权限的用户可创建链式受限基础模型的模型并调用。

CVSS 7.6 · High EPSS 0.30% · P22

Affected Version Matrix 1

VendorProduct Version RangeStatus
open-webui open-webui < 0.9.0 affected
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I. Basic Information for CVE-2026-44555

Vulnerability Information
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Vulnerability Title
Open WebUI: Base Model Routing Bypasses Access Control via Model Chaining
Source: CVE Program / CVE List V5
Vulnerability Description
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, Open WebUI supports model composition via base_model_id: a user-defined model (e.g., "Cheap Assistant") can reference an existing base model (e.g., "gpt-4-turbo-restricted") that provides the actual inference capability. When a user queries the composed model, the access control pipeline verifies the user has access to the composed model but never re-verifies access to the chained base model. Additionally, the model creation and import endpoints accept arbitrary base_model_id values without checking that the caller has access to that base model. Combined, this allows any user with the default model creation permission to create a model that chains to a restricted base model — and then invoke it, causing the server to dispatch the request to the restricted base model using the admin-configured API key. This vulnerability is fixed in 0.9.0.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
授权机制缺失
Source: CVE Program / CVE List V5
Vulnerability Title
Open WebUI 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Open WebUI是Open WebUI开源的一个可扩展、功能丰富、用户友好的自托管 WebUI。 Open WebUI 0.9.0之前版本存在安全漏洞，该漏洞源于模型组合功能中，访问控制管道仅验证用户对组合模型的访问权限，但未重新验证对链式基础模型的访问权限，且模型创建和导入端点接受任意base_model_id值而不检查调用者是否有权访问该基础模型，导致任何具有默认模型创建权限的用户可创建链式受限基础模型的模型并调用。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
open-webui open-webui < 0.9.0 -

II. Public POCs for CVE-2026-44555

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III. Intelligence Information for CVE-2026-44555

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Vendor Advisories for CVE-2026-44555 (1)

Same Patch Batch · open-webui · 2026-05-15 · 59 CVEs total

CVE-2026-44551 9.1 CRITICAL Open WebUI: LDAP Empty Password Authentication Bypass
CVE-2026-45672 8.8 HIGH Open WebUI: Jupyter code execution works despite `ENABLE_CODE_EXECUTION=false` — feature g
CVE-2026-45315 8.7 HIGH Open WebUI: Stored XSS via attacker-controlled file extension in /api/v1/audio/transcripti
CVE-2026-44552 8.7 HIGH Open WebUI: Redis Cache Keys tool_servers and terminal_servers Missing Instance Prefix Ena
CVE-2026-45331 8.5 HIGH Open WebUI: Full SSRF Vulnerability in the RAG Web Search Feature
CVE-2026-45400 8.5 HIGH Open WebUI: Server-Side Request Forgery (SSRF) bypass in `validate_url`
CVE-2026-45401 8.5 HIGH Open WebUI: SSRF Bypass via HTTP Redirect Following in Web-Fetch and Image-Load Endpoints
CVE-2026-44570 8.3 HIGH Open WebUI: Inconsistent authorization controls within memories API
CVE-2026-44565 8.1 HIGH Open WebUI: Open WebUI Arbitrary File Write, Delete via Path Traversal
CVE-2026-45675 8.1 HIGH Open WebUI: LDAP and OAuth First-User Race Condition Allows Multiple Admin Accounts
CVE-2026-44553 8.1 HIGH Open WebUI: Stale Admin Role in Socket.IO Session Pool Enables Post-Demotion Cross-User No
CVE-2026-44554 8.1 HIGH Open WebUI: Knowledge Base Destruction and RAG Poisoning via Unauthorized Collection Overw
CVE-2026-45301 8.1 HIGH Open WebUI: Missing permission check in files API allows authenticated users to list, acce
CVE-2026-45665 8.1 HIGH Open WebUI: Stored XSS in Banner Component via Improper Sanitization Order
CVE-2026-45402 8.1 HIGH Open WebUI: Cross-User File Access via Unchecked file_id in Folder Knowledge and Knowledge
CVE-2026-45671 8.0 HIGH Open WebUI: shared-chat branch ignores access_type, allowing unauthorized file deletion
CVE-2026-45338 7.7 HIGH Open WebUI: SSRF via OAuth Profile Picture URL in _process_picture_url (oauth.py)
CVE-2026-45303 7.7 HIGH Open WebUI: Stored XSS via the HTML renedering view
CVE-2026-45398 7.5 HIGH Open WebUI: IDOR - Retrieval API Bypasses Knowledge Base Access Controls
CVE-2026-44566 7.3 HIGH Open WebUI: Arbitrary File Upload and Path Traversal

Showing top 20 of 59 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: open-webui
Same vendor: open-webui
Same weakness: CWE-862

V. Comments for CVE-2026-44555

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