CVE-2026-67528Network attack vector

Authenticated disclosure via unscoped custom-option lookup

Published Jul 30, 2026 · Updated Jul 30, 2026

Improper access control in OpenProject before 17.6.0 allows remote authenticated users to read hidden custom-option labels. GET /api/v3/custom_options/:id resolves a CustomOption by global numeric ID and permits user or group field options without checking whether the owning field is visible. Any normal account can enumerate sequential IDs, but the exposure is limited to labels from admin-only user and group custom fields.

CVSS severity4.3
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in OpenProject before 17.6.0 allows remote authenticated users to read hidden custom-option labels. GET /api/v3/custom_options/:id resolves a CustomOption by global numeric ID and permits user or group field options without checking whether the owning field is visible. Any normal account can enumerate sequential IDs, but the exposure is limited to labels from admin-only user and group custom fields.

The record

CVE
CVE-2026-67528
Published
Jul 30, 2026
Updated
Jul 30, 2026
Vendor
OpenProject GmbH
Product
OpenProject
Classifications
T1213
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 30, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 30, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 17.6.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

OpenProject GmbH · OpenProjectversion=< 17.6.0

Published CVSS scores

4.3GitHub Security AdvisoryCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1213Data from Information Repositories

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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