CVE-2026-25877: Chartbrew Authorization Bypass Vulnerability

CVE-2026-25877 Overview

CVE-2026-25877 is an Insecure Direct Object Reference (IDOR) vulnerability affecting Chartbrew, an open-source web application used to connect directly to databases and APIs to create data visualizations. Prior to version 4.8.1, the application performs authorization checks based solely on the project_id parameter when handling chart-related operations (update, delete, etc.), without validating authorization against the chart_id itself. This flaw allows an authenticated user with access to any project to manipulate or access charts belonging to other users or projects.

Critical Impact

Authenticated attackers can bypass authorization controls to view, modify, or delete charts belonging to other users and projects, potentially compromising data integrity and confidentiality across the entire Chartbrew deployment.

Affected Products

• Depomo Chartbrew versions prior to 4.8.1

Discovery Timeline

• 2026-03-06 - CVE CVE-2026-25877 published to NVD
• 2026-03-10 - Last updated in NVD database

Technical Details for CVE-2026-25877

Vulnerability Analysis

This vulnerability is classified under CWE-284 (Improper Access Control) and CWE-639 (Authorization Bypass Through User-Controlled Key). The core issue lies in the application's flawed authorization model for chart-related operations. When a user performs actions such as updating or deleting a chart, the application validates whether the user has access to the associated project_id but fails to verify that the specified chart_id actually belongs to that project.

This architectural weakness creates a horizontal privilege escalation scenario where any authenticated user can reference chart identifiers from other users' projects. Since the chart_id is a user-controllable parameter and the backend does not enforce proper ownership validation, attackers can enumerate and manipulate charts across the entire application.

Root Cause

The root cause is insufficient authorization granularity in the chart management endpoints. The application's access control logic trusts that if a user has access to any project, they should be able to manipulate any chart by specifying its ID, without verifying that the chart belongs to an authorized project. This represents a classic Insecure Direct Object Reference pattern where object-level authorization is missing.

Attack Vector

An attacker with valid credentials and access to at least one project can exploit this vulnerability remotely over the network. The attack requires no user interaction and can be executed with low complexity. By intercepting or crafting API requests to chart management endpoints, the attacker can substitute the chart_id parameter with identifiers belonging to charts in other users' projects.

The attack flow involves:

1. Authenticating to Chartbrew with a valid user account
2. Identifying or enumerating chart IDs (potentially through sequential guessing or information leakage)
3. Sending API requests for chart operations (update, delete, view) with the target chart_id
4. The server validates access to the attacker's own project but processes the request against the victim's chart

Since no exploit code has been publicly released for this vulnerability, organizations should review the GitHub Security Advisory GHSA-9fcr-x8x8-mrxc for additional technical details on the vulnerable code paths.

Detection Methods for CVE-2026-25877

Indicators of Compromise

• Unusual API activity patterns where chart operations reference chart_id values not associated with the requesting user's authorized projects
• Audit logs showing users accessing or modifying charts outside their normal project scope
• Cross-project chart access patterns in application logs that indicate enumeration attempts
• Failed or successful chart operations with mismatched project_id and chart_id relationships

Detection Strategies

• Implement API request logging that captures both project_id and chart_id parameters for correlation analysis
• Deploy application-layer monitoring to detect sequential or brute-force chart ID enumeration attempts
• Configure alerting for chart operations where the requesting user's project membership does not match the target chart's project
• Review access logs for authenticated users performing operations across multiple unrelated projects

Monitoring Recommendations

• Enable verbose logging for all chart management API endpoints (/api/charts, update, and delete operations)
• Monitor for anomalous patterns of chart access that span multiple projects from a single user session
• Establish baseline metrics for normal chart operation volumes per user to detect enumeration behavior
• Integrate Chartbrew logs with SIEM solutions for cross-correlation with authentication events

How to Mitigate CVE-2026-25877

Immediate Actions Required

• Upgrade Chartbrew to version 4.8.1 or later immediately to remediate this vulnerability
• Audit existing chart data for unauthorized modifications by reviewing application logs
• Review user access patterns to identify potential exploitation attempts prior to patching
• Consider temporarily restricting chart management operations to administrative users if immediate patching is not possible

Patch Information

Depomo has released version 4.8.1 of Chartbrew which addresses this authorization bypass vulnerability. The patch implements proper object-level authorization checks to verify that the chart_id belongs to a project the requesting user is authorized to access. Organizations should upgrade to this version or later as soon as possible.

For patch details, see the GitHub Release v4.8.1.

Workarounds

• Implement network-level access controls to limit Chartbrew access to trusted users only
• Deploy a web application firewall (WAF) with custom rules to validate chart ownership in API requests
• Temporarily disable chart update and delete functionality via API gateway policies until patching is completed
• Enable additional authentication factors for users with chart management permissions

# Example: Restrict Chartbrew API access at the network level
# Add to nginx configuration to limit access to internal networks
location /api/charts {
    allow 10.0.0.0/8;
    allow 192.168.0.0/16;
    deny all;
    proxy_pass http://chartbrew-backend;
}