Auth bypass in Opf Openproject
CVE-2026-52779
OpenProject is open-source, web-based project management software. Prior to 17.3.3 and 17.4.1, a cross-project IDOR / authorization context confusion in the Calendar and Team Planner modules allows a user with management permissions in one project to delete public Calendar or Team Planner Queries from another project where they do not have the corresponding management permissions. Both modules authorize the request against the project identified by :project_id in the URL, but the actual Query object is loaded later by :id from Query.visible(current_user) without verifying that the loaded Query belongs to the authorized project. As a result, an attacker can use permissions from Project A to delete shared/public Calendar or Team Planner views from Project B, causing integrity impact and limited availability impact for users relying on those shared views. 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 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L.
EPSS exploit prediction
EPSS: 0.003 (21.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 22nd percentile — 21.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
- Opf Openproject — versions < 17.3.3, >= 17.4.0, < 17.4.1
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-52779?
- CVE-2026-52779 is a medium-severity vulnerability in Opf Openproject, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 5.4/10. Published 2026-06-26.
- How severe is CVE-2026-52779?
- Medium severity. CVSS v3 base score is 5.4 out of 10.