CVE-2026-35446
Mcgill Loris 24.0.0 – 27.0.2
Raw vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:NSummary
CVE-2026-35446 is a high-severity Files or Directories Accessible to External Parties (CWE-552) vulnerability in Mcgill Loris. Its CVSS base score is 7.7 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Data from Local System (T1005); ranked at the 14th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and AC-6 (Least Privilege) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-35446 is a directory traversal vulnerability in LORIS, a self-hosted web application for data and project management in neuroimaging research. The issue stems from an incorrect order of operations in the FilesDownloadHandler, affecting versions from 24.0.0 up to but not including 27.0.3 and 28.0.1. This flaw, classified under CWE-552 (Files or Directories Accessible to External Parties), carries a CVSS v3.1 base score of 7.7 (AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N), indicating high severity due to its potential for unauthorized data access.
An attacker with low-privilege authenticated access (PR:L) can exploit this vulnerability over the network (AV:N) with low complexity (AC:L) and no user interaction required (UI:N). By manipulating download requests, they can escape the intended download directories, achieving high-impact confidentiality breaches (C:H) in a scoped manner (S:C), such as reading sensitive files outside the restricted paths, while integrity and availability remain unaffected.
The GitHub security advisory (GHSA-47jj-7xfg-8759) confirms the vulnerability and states it is fixed in LORIS versions 27.0.3 and 28.0.1. Security practitioners should upgrade to these patched releases to mitigate the issue, ensuring all instances of affected versions are updated promptly.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-20580
Vulnerability Data
LORIS (Longitudinal Online Research and Imaging System) is a self-hosted web application that provides data- and project-management for neuroimaging research. From 24.0.0 to before 27.0.3 and 28.0.1, an incorrect order of operations in the FilesDownloadHandler could result in an attacker…
more
escaping the intended download directories. This vulnerability is fixed in 27.0.3 and 28.0.1.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 5 hardening rules · 2 OS baselines
V8.4.2
Mitigating Controls (NIST 800-53 r5) AI
AC-3 directly enforces authorization checks on access to files and directories, stopping unauthorized external exposure.
AC-6 limits granted privileges, reducing the chance that files or directories become reachable by external parties.
AC-4 enforces information flow rules that can block unauthorized external access to files or directories.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Enforcing least-privilege permissions and authorization policies directly prevents unauthorized file/directory exposure.
Logical segmentation and access protections stop external parties from reaching files that should remain internal.
Data-at-rest protections such as encryption or ACLs reduce the impact of unintended file exposure.
Hardened configuration baselines commonly include file-system permission settings that limit external access.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
By tracing and retrieving all copies of information stored on endpoint and portable devices, the control reduces the likelihood that files remain accessible outside the organization’s security perimeter.
Labeling information according to its sensitivity and specifying corresponding protection measures makes it less probable that files or directories containing sensitive content will be left accessible to external parties.
Including asset location and ownership in the inventory, combined with secure disposal procedures, decreases the chance that files or directories remain accessible to external parties after they should have been removed or restricted.
Solid perimeters and locked external access points stop files, devices, or directories containing sensitive data from being reachable by external parties who could otherwise walk in or break in.
Authorizing and logging the removal of storage media, disabling unused ports, and monitoring transfers limit the exposure of files or directories to external parties outside the organization’s controlled environment.
Segregating delivery/loading zones and controlling external doors prevents external parties from reaching directories or resources that should remain inaccessible.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).
Oracle Linux 8 (2 rules)
- V-248579 OL 8 must restrict access to the kernel message buffer. prevents CWE-552
- V-248597 There must be no "shosts.equiv" files on the OL 8 operating system. prevents CWE-552