CVE-2026-67527 in OpenProject
Summary
by MITRE • 07/30/2026
OpenProject is open-source, web-based project management software. Prior to 17.6.0, PATCH /api/v3/work_packages/{id} accepted _links.fileLinks and allowed authenticated users with edit_work_packages but without manage_file_links to resolve Storages::FileLink records by raw id, detach or hard-delete existing FileLinks, and re-parent FileLinks from other projects to an attacker-controlled work package, exposing origin filename, origin id, and MIME type metadata. This issue is fixed in 17.6.0.
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Analysis
by VulDB Data Team • 07/30/2026
This vulnerability exists within OpenProject's API endpoint handling for work package file link management, specifically affecting versions prior to 17.6.0. The flaw manifests in the PATCH operation targeting /api/v3/work_packages/{id} which processes _links.fileLinks parameter submissions. Authentication is required but the privilege model contains a critical gap allowing users with edit_work_packages permissions but lacking manage_file_links rights to exploit this vulnerability, creating a privilege escalation scenario through improper access control implementation.
The technical exploitation occurs through manipulation of FileLink records using their raw database identifiers, enabling attackers to perform unauthorized operations on file link associations. This includes resolving existing FileLink records by their internal IDs, detaching them from their original context, and performing hard deletions that permanently remove file link references. The vulnerability extends beyond simple data manipulation to include re-parenting functionality that allows attackers to transfer file links between projects, effectively bypassing project-level access controls.
From a security perspective, this vulnerability represents a serious information disclosure risk as it exposes metadata from the original file sources including filenames, internal identifiers, and MIME type information. The exposure occurs during the process of manipulating file link associations, creating a data leak that could reveal sensitive information about the source files and their organizational structure within the system. This metadata exposure can aid attackers in planning further exploitation attempts or understanding the underlying data architecture.
The operational impact of this vulnerability is significant for organizations using OpenProject as their project management solution, particularly those with multiple projects where file link management is critical. Attackers could manipulate file link associations to redirect attachments to different work packages, potentially causing confusion in project tracking while simultaneously gaining unauthorized access to file metadata from other projects. This cross-project information leakage represents a violation of data isolation principles and could compromise the integrity of project data relationships.
The fix implemented in version 17.6.0 addresses this issue through proper access control enforcement that validates user permissions before allowing FileLink manipulation operations. This change aligns with the principle of least privilege and ensures that users cannot perform file link management operations without appropriate authorization levels. The mitigation approach follows standard security practices for API endpoint protection and demonstrates proper implementation of authorization checks within RESTful services.
This vulnerability type maps to CWE-284 (Improper Access Control) and specifically relates to insufficient authorization checks in API endpoints where parameter manipulation can lead to unauthorized data access and modification. The ATT&CK framework categorizes this under privilege escalation techniques through API manipulation, where attackers leverage weak access controls in web applications to gain elevated capabilities within the system.
Organizations should immediately upgrade to OpenProject 17.6.0 or later versions to remediate this vulnerability and ensure proper access control enforcement for file link operations. Additionally, implementing comprehensive logging of file link manipulation activities can help detect unauthorized attempts to exploit this vulnerability during the transition period. Security monitoring should focus on unusual patterns of file link re-association or metadata exposure that could indicate exploitation attempts.