Auth bypass in Opf Openproject

CVE-2026-44731

OpenProject is open-source, web-based project management software. Prior to 17.3.2 and 17.4.0, the web application's meetings filter feature leaks whether a given user ID corresponds to a valid account and discloses the user's full name, allowing an attacker to enumerate all existing user accounts by probing user IDs and observing differences in the server response. This vulnerability is fixed in 17.3.2 and 17.4.0.

Vulnerability class: IDOR (Insecure Direct Object Reference)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.003 (19.7th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 20th percentile — 19.7% 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-2026-44731: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-44731?
CVE-2026-44731 is a medium-severity vulnerability in Opf Openproject, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 4.3/10. Published 2026-06-26.
How severe is CVE-2026-44731?
Medium severity. CVSS v3 base score is 4.3 out of 10.