CVE-2026-4230: Vanna-AI Vanna SQL Injection Vulnerability

CVE-2026-4230 Overview

CVE-2026-4230 is a SQL injection vulnerability affecting vanna-ai vanna versions up to 2.0.2. The flaw resides in the update_sql function within src/vanna/legacy/flask/__init__.py, which is exposed through a Flask endpoint. Attackers can exploit the issue remotely with low-privileged access by manipulating input passed to the function. The vendor was contacted prior to public disclosure but did not respond. A proof-of-concept exploit has been published, increasing the likelihood of opportunistic attacks against exposed deployments [CWE-74].

Critical Impact

Remote attackers with low privileges can inject SQL statements through the update_sql endpoint, potentially altering or exposing data managed by the vanna-ai application.

Affected Products

• vanna-ai vanna up to and including version 2.0.2
• Component: update_sql function in src/vanna/legacy/flask/__init__.py
• Deployments exposing the legacy Flask endpoint to untrusted networks

Discovery Timeline

• 2026-03-16 - CVE-2026-4230 published to NVD
• 2026-04-29 - Last updated in NVD database

Technical Details for CVE-2026-4230

Vulnerability Analysis

The vulnerability is a SQL injection flaw classified under [CWE-74] (Improper Neutralization of Special Elements in Output). The vulnerable code lives in the update_sql function of the legacy Flask interface bundled with vanna-ai. The function accepts attacker-controlled input and incorporates it into a SQL statement without proper sanitization or parameterization. Because vanna-ai operates as a natural language to SQL tool that interacts directly with backing databases, injected SQL is executed in the same database context the application uses for legitimate queries.

Root Cause

The root cause is the absence of parameterized queries or input validation in the update_sql handler. User-supplied data is concatenated into a SQL statement, allowing attackers to break out of the intended query structure. The legacy Flask component does not enforce strict input typing or escaping before passing values to the database driver.

Attack Vector

The attack vector is network-based. An authenticated attacker with low privileges sends a crafted HTTP request to the exposed update_sql endpoint. The injected payload modifies the SQL statement executed by the backend database. Successful exploitation can lead to unauthorized data modification, disclosure of stored records, or further pivoting depending on the privileges of the database account used by the application.

A proof-of-concept has been published on GitHub Gist. See the GitHub Gist PoC Repository and the VulDB #351153 entry for technical details.

Detection Methods for CVE-2026-4230

Indicators of Compromise

• HTTP POST or PUT requests to the update_sql endpoint containing SQL metacharacters such as single quotes, semicolons, UNION, or comment sequences (--, /*)
• Unexpected database queries originating from the vanna-ai service account outside normal application workflows
• Application logs showing malformed or syntactically unusual SQL statements generated by src/vanna/legacy/flask/__init__.py

Detection Strategies

• Inspect Flask access logs for requests targeting update_sql with anomalous payload lengths or encoded SQL keywords
• Enable database query logging and correlate executed statements against expected application templates
• Deploy a web application firewall rule set to flag SQL injection patterns on routes served by the legacy Flask blueprint

Monitoring Recommendations

• Monitor outbound traffic from the vanna-ai host for unusual data volumes that may indicate exfiltration
• Alert on database errors returned to the application, which often accompany SQL injection probing
• Track authentication events for the low-privileged accounts capable of invoking update_sql

How to Mitigate CVE-2026-4230

Immediate Actions Required

• Restrict network access to the vanna-ai Flask endpoint so it is reachable only by trusted clients
• Disable or remove the legacy Flask interface in src/vanna/legacy/flask/__init__.py if it is not required
• Audit existing logs for prior invocations of update_sql containing suspicious input
• Rotate database credentials used by the vanna-ai application and reduce the database account to least privilege

Patch Information

No vendor patch has been published. The vendor did not respond to disclosure attempts. Track the VulDB #351153 entry and the upstream vanna-ai repository for any future fixes. Until a patch is available, treat all deployments running versions up to 2.0.2 as exposed.

Workarounds

• Place the application behind a reverse proxy that enforces authentication and filters SQL injection payloads
• Apply a web application firewall signature targeting requests to the update_sql route
• Replace the legacy Flask handler with a custom wrapper that uses parameterized queries and strict input validation
• Limit the database role used by vanna-ai to read-only access where business requirements allow