CVE-2026-6977: Vanna-AI Auth Bypass Vulnerability

CVE-2026-6977 Overview

A security vulnerability has been detected in vanna-ai vanna up to version 2.0.2. The affected element is an unknown function of the component Legacy Flask API. The manipulation leads to improper authorization (CWE-266: Incorrect Privilege Assignment). It is possible to initiate the attack remotely. The exploit has been disclosed publicly and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

Critical Impact

This improper authorization vulnerability in the vanna-ai vanna Legacy Flask API allows remote attackers to bypass access controls, potentially gaining unauthorized access to resources and functionality that should be restricted.

Affected Products

• vanna-ai vanna versions up to 2.0.2
• Legacy Flask API component within vanna

Discovery Timeline

• 2026-04-25 - CVE-2026-6977 published to NVD
• 2026-04-29 - Last updated in NVD database

Technical Details for CVE-2026-6977

Vulnerability Analysis

This vulnerability affects the Legacy Flask API component within vanna-ai vanna, a tool designed to assist with AI-powered SQL query generation. The flaw stems from improper authorization checks that fail to adequately validate user permissions before granting access to protected resources or functionality.

The vulnerability is classified under CWE-266 (Incorrect Privilege Assignment), indicating that the application incorrectly assigns or fails to revoke privileges, allowing users to access resources or perform actions beyond their intended authorization level. The network-accessible attack vector means that exploitation does not require local access to the target system, significantly expanding the potential attack surface.

Root Cause

The root cause of this vulnerability lies in the Legacy Flask API's failure to implement proper authorization controls. The API endpoints do not adequately verify whether the requesting user has appropriate permissions to access the requested resources. This may result from missing authorization middleware, improperly configured access control lists, or a fundamental design flaw in how the legacy API handles authentication tokens and session management.

Attack Vector

The vulnerability can be exploited remotely over the network without requiring user interaction. An attacker can craft malicious requests to the Legacy Flask API endpoints to bypass authorization checks and gain access to restricted functionality. The attack requires no authentication or special privileges to initiate, making it particularly dangerous for internet-facing deployments of the vanna application.

The vulnerability manifests in the authorization handling of the Legacy Flask API component. Technical details and proof-of-concept information can be found in the GitHub Issue Tracker Entry and the VulDB Vulnerability Listing.

Detection Methods for CVE-2026-6977

Indicators of Compromise

• Unusual API requests to Legacy Flask API endpoints from unexpected IP addresses or user agents
• Access logs showing requests to restricted endpoints without proper authorization headers
• Anomalous patterns of API calls that bypass normal application workflow
• Elevated resource access from accounts that should have limited privileges

Detection Strategies

• Implement API request logging and monitor for unauthorized access patterns to Legacy Flask API endpoints
• Deploy web application firewalls (WAF) configured to detect and block authorization bypass attempts
• Use SentinelOne Singularity XDR to monitor for anomalous application behavior and unauthorized access attempts
• Review Flask application logs for requests that return successful responses without proper authentication

Monitoring Recommendations

• Enable detailed logging for all Flask API endpoints, particularly legacy components
• Configure alerting for failed and successful authorization attempts to sensitive endpoints
• Monitor for unusual traffic patterns to the vanna application, especially from external sources
• Implement behavioral analysis to detect privilege escalation or unauthorized data access

How to Mitigate CVE-2026-6977

Immediate Actions Required

• Assess whether your vanna-ai vanna deployment exposes the Legacy Flask API to untrusted networks
• Implement network-level access controls to restrict access to the API from trusted sources only
• Review application logs for any signs of exploitation or unauthorized access attempts
• Consider disabling or removing the Legacy Flask API component if not required for operations

Patch Information

At the time of disclosure, the vendor (vanna-ai) was contacted but did not respond. No official patch is currently available. Organizations should monitor the VulDB Vulnerability Listing and the official vanna-ai repository for updates regarding security fixes.

Workarounds

• Restrict network access to the Legacy Flask API using firewall rules to allow only trusted IP addresses
• Implement an authentication proxy or API gateway in front of the vanna application to enforce authorization
• Disable the Legacy Flask API component entirely if it is not essential to operations
• Deploy runtime application self-protection (RASP) solutions to detect and block exploitation attempts

# Example: Restrict access to vanna Flask API using iptables
# Allow only trusted internal network (adjust as needed)
iptables -A INPUT -p tcp --dport 5000 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 5000 -j DROP

# Alternatively, use nginx as a reverse proxy with basic auth
# nginx configuration snippet
# location /api/legacy {
#     auth_basic "Restricted Access";
#     auth_basic_user_file /etc/nginx/.htpasswd;
#     proxy_pass http://localhost:5000;
# }