CVE-2026-54007
Summary
by MITRE • 06/23/2026
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.6, the chat message listener allows non-same-origin input:prompt and action:submit messages, so an external site can set prompt text and trigger submitPrompt() in an authenticated victim session. I validated this with a cross-origin attacker page that auto-posted messages and caused unauthorized POST /api/v1/chats/new and POST /api/chat/completions requests containing attacker-controlled prompts. This enables cross-site forced actions and model/tool execution under victim privileges without consent. This vulnerability is fixed in 0.9.6.
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Analysis
by VulDB Data Team • 06/23/2026
This vulnerability resides within Open WebUI, a self-hosted artificial intelligence platform designed to operate entirely offline, making it a critical concern for organizations relying on local AI infrastructure. The flaw manifests as a cross-site request forgery vulnerability that allows external sites to manipulate authenticated user sessions through improper input validation. Prior to version 0.9.6, the chat message listener failed to properly validate origin constraints, permitting non-same-origin messages to be processed as legitimate inputs. This design deficiency creates a dangerous attack vector where malicious actors can craft cross-origin pages that automatically submit messages to authenticated sessions.
The technical exploitation of this vulnerability follows a well-defined pattern that aligns with established attack methodologies documented in the ATT&CK framework under technique T1566 for credential access and T1071 for application layer protocol usage. Attackers can construct malicious web pages that utilize the victim's authenticated session to automatically post messages containing attacker-controlled prompts to the platform's API endpoints. Specifically, the vulnerability enables unauthorized POST requests to /api/v1/chats/new and /api/chat/completions endpoints, which are typically protected by authentication mechanisms. The flaw allows these requests to be executed with the victim's privileges, effectively bypassing access controls that should normally prevent unauthorized operations.
The operational impact of this vulnerability extends beyond simple data exfiltration or session hijacking, as it enables what cybersecurity professionals term "cross-site forced actions" that can lead to unauthorized execution of model inference and tool usage. When an attacker triggers submitPrompt() through a cross-origin page, they can compel the victim's system to process arbitrary prompts through the AI platform's backend services, potentially consuming computational resources, generating unauthorized outputs, or even executing commands if the underlying infrastructure is improperly configured. The severity escalates when considering that these operations occur under the victim's authenticated context, making them indistinguishable from legitimate user activities and complicating detection efforts.
This vulnerability directly corresponds to CWE-352, which describes Cross-Site Request Forgery (CSRF) conditions where applications fail to validate the origin of requests. The flaw demonstrates a classic lack of proper input validation and origin verification mechanisms within the application's message processing pipeline. Organizations using Open WebUI versions prior to 0.9.6 face significant risk as this vulnerability essentially allows attackers to perform unauthorized actions on behalf of authenticated users without their knowledge or consent. The attack surface is particularly concerning given that Open WebUI operates in offline environments where traditional network-based detection mechanisms may be less effective.
Mitigation strategies for this vulnerability include updating to version 0.9.6 or later, which implements proper origin validation and input sanitization measures. Security teams should also consider implementing additional protections such as CSRF tokens for critical API endpoints, content security policies that restrict cross-origin communication, and monitoring for unusual patterns in chat completion requests that might indicate automated exploitation attempts. Organizations should review their deployment configurations to ensure that authentication mechanisms are properly enforced and that the application's API endpoints do not inadvertently expose functionality that could be leveraged for unauthorized operations. The fix addresses the root cause by implementing proper same-origin validation within the message listener component, preventing external sites from injecting malicious payloads that could trigger unintended actions within authenticated sessions.