OpenProject: Relations API Filter Bypasses Visibility Scope, Leaking Cross-Project Work Package Subjects

published 2026-06-26 4 mo ago modified 2026-10-25 14 d ago also EUVD-2026-39876

cvss: 6.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 29%
public exploits: 0; none known

OpenProject is open-source, web-based project management software. Prior to 17.4.0, the GET /api/v3/relations endpoint allows any authenticated user to retrieve relations — and the subject (title) of work packages they have no permission to view — by supplying an arbitrary work package ID in the involved, fromId, or toId filter. This bypasses the Relation.visible scope due to a flawed performance optimization in RelationQuery. This vulnerability is fixed in 17.4.0.

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 4 mo ago (2026-06-27)

Exploit prediction

0.36% chance of exploitation in the next 30 days, higher than 29% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/opf/openproject/security/advisories/GHSA-p9gq-hrgh-2645 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Affected products

opf openproject

Classification

Weakness

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

References

github.com /opf/openproject/security/advisories/GHSA-p9gq-hrgh-2645
exploit

Sources

CVE List CVE-2026-44736
NVD CVE-2026-44736

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary