CVE-2026-22605: OpenProject Auth Bypass Vulnerability

CVE-2026-22605 Overview

OpenProject is an open-source, web-based project management software. A broken access control vulnerability exists in OpenProject versions prior to 16.6.3 that allows users with the View Meetings permission on any project to access meeting details of meetings belonging to projects they do not have authorized access to. This represents a significant information disclosure risk in multi-tenant or multi-project environments where project isolation is expected.

Critical Impact

Users with limited permissions can bypass project-level access controls to view confidential meeting information from unauthorized projects, potentially exposing sensitive business discussions, strategic plans, and confidential data.

Affected Products

• OpenProject versions prior to 16.6.3
• OpenProject installations with meetings module enabled
• Multi-project deployments with differentiated access controls

Discovery Timeline

• 2026-01-10 - CVE CVE-2026-22605 published to NVD
• 2026-01-13 - Last updated in NVD database

Technical Details for CVE-2026-22605

Vulnerability Analysis

This vulnerability is classified under CWE-284 (Improper Access Control), indicating a fundamental flaw in how the application enforces authorization boundaries. The issue stems from insufficient permission validation when users request meeting details through the application's API or interface.

In a properly secured system, access to meeting information should be restricted to users who have explicit permissions on the specific project containing the meeting. However, the flawed implementation only checks whether the requesting user has the View Meetings permission on any project within the OpenProject instance, rather than validating project-specific access rights.

This horizontal privilege escalation allows authenticated users to traverse project boundaries and access meeting data they should not be authorized to view. The attack requires network access and low-privilege authentication, making it accessible to any user with basic access to the OpenProject installation.

Root Cause

The root cause is improper access control validation in the meetings functionality. The authorization logic fails to properly scope permission checks to the specific project context, instead accepting a global View Meetings permission as sufficient authorization for accessing any meeting across all projects.

Attack Vector

The vulnerability is exploitable over the network by any authenticated user who holds the View Meetings permission on at least one project. The attacker can craft requests to access meeting details from other projects by referencing meeting IDs or project identifiers they should not have access to. Since OpenProject is a web-based application, this attack can be performed through standard HTTP requests to the application's endpoints.

The attack does not require any user interaction and has low complexity, as it simply involves making authorized API calls with meeting references from unauthorized projects. The vulnerability only affects confidentiality, as it allows reading meeting data but does not permit modification or deletion.

Detection Methods for CVE-2026-22605

Indicators of Compromise

• Unusual patterns of meeting detail access requests across multiple projects by a single user
• API calls or web requests referencing meeting IDs from projects the authenticated user is not a member of
• Access logs showing users querying meeting endpoints for projects outside their assigned scope
• Audit trail anomalies where users access meeting information without corresponding project membership

Detection Strategies

• Implement logging and monitoring of all meeting detail access requests with project context validation
• Configure alerting for cross-project meeting access patterns that violate expected user-project assignments
• Review application logs for users accessing meeting resources outside their project membership scope
• Deploy web application firewall rules to detect potential access control bypass attempts

Monitoring Recommendations

• Enable detailed audit logging for all meeting-related API endpoints
• Monitor for bulk meeting enumeration attempts or sequential meeting ID access patterns
• Implement real-time alerting for users accessing meetings from projects they lack membership in
• Conduct periodic access review audits comparing meeting access logs against project membership records

How to Mitigate CVE-2026-22605

Immediate Actions Required

• Upgrade OpenProject to version 16.6.3 or later immediately
• Review audit logs for any evidence of unauthorized meeting access prior to patching
• Conduct a security assessment of meeting data that may have been exposed
• Notify affected project stakeholders if evidence of exploitation is discovered

Patch Information

OpenProject has released version 16.6.3 which addresses this broken access control vulnerability. The patch implements proper project-scoped permission validation for meeting detail access requests. Organizations should upgrade to this version as the primary remediation measure.

For detailed patch information, see the GitHub Release v16.6.3 and the GitHub Security Advisory GHSA-fq4m-pxvm-8x2j.

Workarounds

• Temporarily disable the meetings module if it is not business-critical until the patch can be applied
• Restrict the View Meetings permission to only highly trusted users across the organization
• Implement network-level access controls to limit exposure of the OpenProject application
• Consider deploying separate OpenProject instances for highly sensitive projects until patching is complete

# Upgrade OpenProject to patched version
# For packaged installations:
sudo openproject configure

# Verify the installed version after upgrade
openproject run bundle exec rails runner "puts OpenProject::VERSION::STRING"

# Review recent meeting access logs for suspicious activity
sudo tail -f /var/log/openproject/production.log | grep -i "meeting"