Auth bypass in Opf Openproject

CVE-2026-52782

OpenProject is open-source, web-based project management software. Prior to 17.3.3 and 17.4.1, there is an IDOR through /projects/<A>/settings/project_storages/<A_ps_id> via PATCH parameter "storages_project_storage[project_folder_id]" leads to Access to Unauthorized Resources. A project-admin in one project can hijack the managed Nextcloud or OneDrive folder of another project on the same storage by writing the victim project's project_folder_id into the attacker's Storages::ProjectStorage row. The next managed-folder sync overwrites the ACL on the referenced folder with the attacker project's user list. This vulnerability is fixed in 17.3.3 and 17.4.1.

Vulnerability class: IDOR (Insecure Direct Object Reference)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.9 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.005 (36.9th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 36.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-52782: held from 0.005 to 0.005.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2026-52782?
CVE-2026-52782 is a critical-severity vulnerability in Opf Openproject, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 9.9/10. Published 2026-06-26.
How severe is CVE-2026-52782?
Critical severity. CVSS v3 base score is 9.9 out of 10.
Is CVE-2026-52782 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.