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Information disclosure on OpenProject through /api/v3/custom_fields/{id}/items

Moderate
klaustopher published GHSA-qpg6-635j-wjc2 Feb 26, 2026

Software

OpenProject

Affected versions

< 17.0.5

Patched versions

17.0.5, 17.1.2

Description

The api implementation for custom_fields lacks any validation that the current user is authorized on any project using the custom_field data. This leaks potentially sensitive, project specific business logic.

Credits

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

Severity

Moderate

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
None
Availability
None

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:N/A:N

CVE ID

CVE-2026-27716

Weaknesses

No CWEs