Auth bypass in Aces Loris
CVE-2026-35165
LORIS (Longitudinal Online Research and Imaging System) is a self-hosted web application that provides data- and project-management for neuroimaging research. From 21.0.0 to before 27.0.3 and 28.0.1, while the document_repository frontend was restricting file access, the backend endpoint was not correctly verifying access permissions. A user could theoretically download a file that they should not have access to, if they know or can brute force the filename. This vulnerability is fixed in 27.0.3 and 28.0.1.
Vulnerability class: IDOR (Insecure Direct Object Reference)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L.
EPSS exploit prediction
EPSS: 0.003 (17.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 18th percentile — 17.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
- Aces Loris — versions >= 21.0.0, < 27.0.3, >= 28.0.0, < 28.0.1
- Mcgill Loris — versions 28.0.0
Weakness classification (CWE)
References
- github.com/aces/Loris/security/advisories/GHSA-qp6x-qfx7-54wp (Patch, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-35165?
- CVE-2026-35165 is a medium-severity vulnerability in Aces Loris, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 6.3/10. Published 2026-04-08.
- How severe is CVE-2026-35165?
- Medium severity. CVSS v3 base score is 6.3 out of 10.