CVE-2026-44736Network attack vector

Cross-project subject disclosure via one-sided visibility checks

Published Jun 26, 2026 · Updated Jun 26, 2026

Improper access control in OpenProject before 17.4.0 allows remote authenticated users to read hidden work package subjects via API filters. RelationQuery treats involved, fromId, and toId filters as visibility-checked even though each validates only the opposite relation endpoint, so it skips Relation.visible and the representer emits both subjects. An account with work-package viewing rights in one project can enumerate guessed IDs and disclose subjects and relation metadata from inaccessible projects.

CVSS severity6.5
Medium
EPSS probability0.39%
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 17.4.0 allows remote authenticated users to read hidden work package subjects via API filters. RelationQuery treats involved, fromId, and toId filters as visibility-checked even though each validates only the opposite relation endpoint, so it skips Relation.visible and the representer emits both subjects. An account with work-package viewing rights in one project can enumerate guessed IDs and disclose subjects and relation metadata from inaccessible projects.

The record

CVE
CVE-2026-44736
Published
Jun 26, 2026
Updated
Jun 26, 2026
Vendor
OpenProject GmbH
Product
OpenProject
Classifications
CWE-200, CWE-836, CWE-639, T1213
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 26, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 26, 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=< 17.4.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

OpenProject GmbH · OpenProjectversion=< 17.4.0

Published CVSS scores

6.5OpenProjectCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/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

CWE-200Exposure of Sensitive Information to an Unauthorized Actor
CWE-836Use of Password Hash Instead of Password for Authentication
CWE-639Authorization Bypass Through User-Controlled Key
T1213Data from Information Repositories

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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