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Improper Access Control on openproject through /api/v3/work_packages/<X.id> via PATCH parameter "fileLinks"

High
oliverguenther published GHSA-c6rc-4288-8p4f Jul 8, 2026

Software

OpenProject

Affected versions

< 17.6.0

Patched versions

17.6.0

Description

PATCH /api/v3/work_packages/{id} accepts a writable _links.fileLinks payload property. The update path is missing the user_allowed_to_manage_file_links validation that exists on the create path, and the underlying setter resolves Storages::FileLink records by raw id with no scope. An authenticated user with only edit_work_packages (no manage_file_links, no membership in the victim project) can therefore:

  • detach (and, via dependent: :delete_all, hard-delete) every FileLink currently attached to a work package they can edit, and

  • re-parent any FileLink in the database, identified by its numeric id, onto an attacker-controlled work package, gaining read access to its metadata (origin filename, origin id, mime type) and removing it from the victim's work package.

Credits

This vulnerability was reported as part of the YesWeHack.com OpenProject Bug Bounty program, sponsored by the European Commission.

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
High
Availability
Low

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:L

CVE ID

CVE-2026-67527

Weaknesses

No CWEs