CVE-2026-4993: wandb OpenUI Auth Bypass Vulnerability

CVE-2026-4993 Overview

A hard-coded credentials vulnerability has been identified in wandb OpenUI affecting versions up to 0.0.0.0/1.0. This security flaw impacts the file backend/openui/config.py where the manipulation of the argument LITELLM_MASTER_KEY exposes hard-coded credentials. The vulnerability requires local access to exploit, and a proof-of-concept exploit has been publicly disclosed. The vendor was contacted early about this disclosure but did not respond.

Critical Impact

Local attackers can potentially extract hard-coded credentials from the application configuration, which could lead to unauthorized access to LiteLLM services or other connected systems.

Affected Products

• wandb OpenUI versions up to 0.0.0.0/1.0

Discovery Timeline

• 2026-03-28 - CVE CVE-2026-4993 published to NVD
• 2026-03-30 - Last updated in NVD database

Technical Details for CVE-2026-4993

Vulnerability Analysis

This vulnerability falls under CWE-259 (Use of Hard-coded Password), a configuration and design flaw where sensitive credentials are embedded directly within the application's source code. The affected component is the configuration file located at backend/openui/config.py, which contains a hard-coded LITELLM_MASTER_KEY value.

Hard-coded credentials represent a significant security risk because they cannot be easily rotated, are visible to anyone with access to the source code or compiled binaries, and persist across deployments. In this case, the exposure requires local access to the system, limiting the attack surface but still presenting a risk in multi-user environments or when the source code is accessible.

Root Cause

The root cause of this vulnerability is the improper handling of sensitive authentication material within the OpenUI application. Rather than retrieving credentials from secure external sources such as environment variables, secrets managers, or encrypted configuration files, the LITELLM_MASTER_KEY credential is directly embedded in the Python configuration file backend/openui/config.py.

This practice violates secure coding principles and makes credential rotation difficult without modifying and redeploying the application code.

Attack Vector

The attack requires local access to the target system. An attacker with local access to the server or development environment can examine the backend/openui/config.py file to extract the hard-coded LITELLM_MASTER_KEY. Once obtained, this credential could potentially be used to authenticate to LiteLLM services or other integrated components that rely on this key.

The vulnerability mechanism involves direct examination of configuration files where credentials are stored in plaintext. For technical details and proof-of-concept information, refer to the GitHub Gist PoC and VulDB #353880.

Detection Methods for CVE-2026-4993

Indicators of Compromise

• Unauthorized access to backend/openui/config.py configuration file
• Unusual authentication attempts using the compromised LITELLM_MASTER_KEY
• Unexpected file access patterns targeting Python configuration files in the OpenUI installation directory

Detection Strategies

• Monitor file access events on backend/openui/config.py for unauthorized read attempts
• Implement file integrity monitoring (FIM) on sensitive configuration files
• Audit authentication logs for LiteLLM services for anomalous access patterns
• Use static code analysis tools to scan for hard-coded credentials in Python files

Monitoring Recommendations

• Enable detailed logging for file system access events on the OpenUI backend directory
• Configure alerts for access to configuration files by non-service accounts
• Monitor for bulk read operations on Python files that may indicate credential harvesting
• Review authentication logs for any services that utilize the LITELLM_MASTER_KEY

How to Mitigate CVE-2026-4993

Immediate Actions Required

• Restrict file system permissions on backend/openui/config.py to only the service account running OpenUI
• Audit access logs to determine if the configuration file has been accessed by unauthorized users
• Rotate the LITELLM_MASTER_KEY immediately and update dependent services
• Consider implementing environment variable-based credential management as a workaround

Patch Information

No official patch is currently available from the vendor. The vendor was contacted early about this disclosure but did not respond. Organizations should implement the workarounds described below and monitor for future security updates.

For additional vulnerability details, see VulDB CTI ID #353880 and VulDB Submission #778265.

Workarounds

• Move the LITELLM_MASTER_KEY credential to environment variables instead of hard-coding in config.py
• Implement a secrets management solution such as HashiCorp Vault or AWS Secrets Manager
• Restrict file system permissions to prevent unauthorized access to configuration files
• Consider using configuration management tools that support encrypted secrets

# Configuration example - Move credentials to environment variables
export LITELLM_MASTER_KEY="your-secure-rotated-key"
# Then modify config.py to read from environment:
# LITELLM_MASTER_KEY = os.environ.get('LITELLM_MASTER_KEY')

# Restrict file permissions on config.py
chmod 600 backend/openui/config.py
chown openui-service:openui-service backend/openui/config.py