CVE-2026-34222: Open WebUI Auth Bypass Vulnerability

CVE-2026-34222 Overview

CVE-2026-34222 is a broken access control vulnerability affecting Open WebUI, a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to version 0.8.11, the platform contains improper authorization (CWE-285) in tool values, allowing authenticated users to access sensitive information beyond their intended permissions. This vulnerability enables attackers with low-privilege access to potentially read confidential data across tenant boundaries.

Critical Impact

Authenticated attackers can exploit broken access control in tool values to access sensitive information from other users or system contexts, potentially leading to significant confidentiality breaches in multi-user AI deployments.

Affected Products

• Open WebUI versions prior to 0.8.11
• Self-hosted Open WebUI installations with multiple users
• Deployments utilizing custom tool configurations

Discovery Timeline

• 2026-04-01 - CVE-2026-34222 published to NVD
• 2026-04-01 - Last updated in NVD database

Technical Details for CVE-2026-34222

Vulnerability Analysis

This vulnerability stems from improper authorization controls (CWE-285) within Open WebUI's tool value handling mechanism. The platform fails to properly validate user permissions when accessing tool configurations and their associated values, creating a broken access control condition that can be exploited by authenticated users.

The network-accessible nature of this vulnerability means that any authenticated user within the Open WebUI environment can potentially access tool values belonging to other users or system-level configurations. Since the attack requires only low-level privileges and no user interaction, exploitation is straightforward once an attacker has basic authentication to the platform. The scope change indicates that the vulnerability can affect resources beyond the vulnerable component's security scope, amplifying the potential for confidentiality breaches.

Root Cause

The root cause lies in improper authorization validation within Open WebUI's tool value access controls. The application fails to enforce proper boundary checks when authenticated users request access to tool configurations, allowing cross-context information retrieval. This represents a classic broken access control pattern where the application assumes authentication is sufficient without implementing proper authorization checks for sensitive resource access.

Attack Vector

The attack vector is network-based and requires low-privilege authenticated access to the Open WebUI platform. An attacker with valid credentials can exploit the broken access control by crafting requests to access tool values that should be restricted to other users or administrative contexts.

The vulnerability allows unauthorized read access to tool configurations and their associated values. Since Open WebUI is designed for AI workloads, these tool values may contain sensitive prompts, API keys, configuration data, or other confidential information that users have configured for their AI assistants.

For detailed technical information about the vulnerability mechanism, refer to the GitHub Security Advisory GHSA-7429.

Detection Methods for CVE-2026-34222

Indicators of Compromise

• Unusual API requests to tool value endpoints from user accounts accessing resources outside their scope
• Increased volume of tool configuration queries from individual user sessions
• Access logs showing authenticated users retrieving tool values they did not create
• Anomalous data access patterns indicating systematic enumeration of tool configurations

Detection Strategies

• Monitor API access logs for requests to tool endpoints that cross user context boundaries
• Implement alerting on rapid sequential access to multiple tool configurations from single sessions
• Deploy application-layer monitoring to detect authorization bypass attempts
• Review audit logs for users accessing tool values without corresponding ownership records

Monitoring Recommendations

• Enable detailed access logging for all tool value retrieval operations
• Configure SIEM rules to correlate tool access patterns with user permissions
• Implement real-time alerting for cross-tenant data access attempts
• Establish baseline tool access patterns for anomaly detection

How to Mitigate CVE-2026-34222

Immediate Actions Required

• Upgrade Open WebUI to version 0.8.11 or later immediately
• Audit existing tool configurations for sensitive data exposure
• Review access logs for potential exploitation attempts prior to patching
• Rotate any API keys or credentials stored in tool values as a precaution

Patch Information

Open WebUI has addressed this vulnerability in version 0.8.11. The patch implements proper authorization checks for tool value access, ensuring users can only access tool configurations within their permitted scope.

For patch details, see the GitHub Release v0.8.11.

The security advisory with additional context is available at the GitHub Security Advisory GHSA-7429.

Workarounds

• Restrict network access to the Open WebUI instance to trusted users only until patching is possible
• Implement network-level segmentation to limit exposure of the vulnerable application
• Avoid storing sensitive information such as API keys or credentials in tool values until the upgrade is complete
• Consider temporarily disabling custom tool functionality if feasible in your deployment

# Upgrade Open WebUI to patched version
# Using Docker (recommended deployment method)
docker pull ghcr.io/open-webui/open-webui:v0.8.11
docker stop open-webui
docker rm open-webui
docker run -d --name open-webui -p 3000:8080 ghcr.io/open-webui/open-webui:v0.8.11