CVE-2026-25530: Kanboard Auth Bypass Vulnerability

CVE-2026-25530 Overview

CVE-2026-25530 is an authorization bypass vulnerability in Kanboard, an open-source project management software focused on the Kanban methodology. Prior to version 1.2.50, the getSwimlane API method lacks project-level authorization, allowing authenticated users to access swimlane data from projects they are not authorized to view. This vulnerability is classified as CWE-639: Authorization Bypass Through User-Controlled Key.

Critical Impact

Authenticated users can access sensitive project data from swimlanes they should not have permission to view, potentially exposing confidential project information across organizational boundaries.

Affected Products

• Kanboard versions prior to 1.2.50
• Kanboard API endpoints using getSwimlane method
• Kanboard API endpoints using getProjectFile method

Discovery Timeline

• 2026-02-10 - CVE-2026-25530 published to NVD
• 2026-02-10 - Last updated in NVD database

Technical Details for CVE-2026-25530

Vulnerability Analysis

The vulnerability exists in Kanboard's API layer where the getSwimlane procedure fails to implement proper project-level authorization checks before returning swimlane data. The SwimlaneProcedure.php file directly returns swimlane information based solely on the swimlane_id parameter without verifying whether the requesting user has access to the associated project. This broken access control allows any authenticated user to enumerate and retrieve swimlane data from any project in the Kanboard instance, regardless of their actual permissions.

Additionally, a similar authorization bypass was identified in the getProjectFile method within ProjectFileProcedure.php, where the file retrieval logic did not validate that the requested file actually belongs to the specified project, enabling authenticated users to potentially access files from unauthorized projects.

Root Cause

The root cause is missing authorization validation in the API procedure layer. The getSwimlane method retrieves swimlane data directly from the model without invoking the ProjectAuthorization check to verify that the authenticated user has permission to access the swimlane's parent project. This is a classic example of Insecure Direct Object Reference (IDOR) where user-supplied identifiers are trusted without proper access control validation.

Attack Vector

An attacker with a valid authenticated session can exploit this vulnerability by calling the getSwimlane API endpoint with arbitrary swimlane IDs. By iterating through swimlane identifiers, an attacker can extract sensitive project management data including swimlane names, descriptions, and configuration from projects they should not have access to. The attack requires only low-privilege authenticated access and can be performed remotely over the network without user interaction.

// Vulnerable code in app/Api/Procedure/SwimlaneProcedure.php (before patch)
public function getSwimlane($swimlane_id)
{
    return $this->swimlaneModel->getById($swimlane_id);
}

// Patched code adds authorization check
public function getSwimlane($swimlane_id)
{
    $swimlane = $this->swimlaneModel->getById($swimlane_id);
    ProjectAuthorization::getInstance($this->container)->check($this->getClassName(), 'getSwimlane', $swimlane['project_id']);
    return $swimlane;
}

Source: GitHub Commit Update

Detection Methods for CVE-2026-25530

Indicators of Compromise

• Unusual API call patterns to getSwimlane endpoints with sequential or random swimlane IDs
• Authenticated users accessing swimlane data for projects not assigned to them
• Elevated API request volume from individual user accounts targeting swimlane retrieval
• Access logs showing getSwimlane requests returning data for multiple unrelated projects

Detection Strategies

• Monitor API logs for getSwimlane method calls and correlate with user project membership
• Implement anomaly detection for users accessing swimlane IDs outside their authorized project scope
• Review authentication logs for patterns suggesting enumeration attacks against swimlane endpoints
• Configure alerting for high-frequency API calls to the swimlane retrieval endpoint

Monitoring Recommendations

• Enable detailed API request logging including user identity, requested swimlane IDs, and response status
• Implement real-time alerting for cross-project data access attempts
• Audit user activity reports for suspicious swimlane access patterns
• Deploy application-level monitoring to track authorization bypass attempts

How to Mitigate CVE-2026-25530

Immediate Actions Required

• Upgrade Kanboard to version 1.2.50 or later immediately
• Review API access logs for evidence of exploitation prior to patching
• Audit user permissions and project access configurations
• Restrict API access to trusted networks if immediate patching is not possible

Patch Information

The vulnerability is fixed in Kanboard version 1.2.50. The patch adds proper ProjectAuthorization checks to the getSwimlane method and also fixes a similar issue in the getProjectFile method. The fix ensures that swimlane data is only returned after validating the requesting user's access to the associated project.

For detailed patch information, see:

• GitHub Release Version 1.2.50
• GitHub Security Advisory GHSA-6rxw-vvvj-r93q
• GitHub Commit Update

Workarounds

• Restrict network access to the Kanboard API using firewall rules until patching is complete
• Implement additional authentication requirements such as API key validation at the network layer
• Disable API access temporarily if not critical to business operations
• Monitor and rate-limit API requests per user to reduce enumeration attack effectiveness

# Example: Restrict API access via reverse proxy (nginx)
location /jsonrpc.php {
    # Limit to internal networks only until patch is applied
    allow 10.0.0.0/8;
    allow 192.168.0.0/16;
    deny all;
    
    # Rate limiting to slow down enumeration attempts
    limit_req zone=api_limit burst=10 nodelay;
    
    proxy_pass http://kanboard_backend;
}