Raw vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:NCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-35169 is a high-severity Cross-site Scripting (CWE-79) vulnerability in Mcgill Loris. Its CVSS base score is 8.7 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Data from Network Shared Drive (T1039); ranked at the 5th 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-2026-35169 is a vulnerability in the help_editor module of LORIS, a self-hosted web application used for data and project management in neuroimaging research. The issue stems from improper sanitization of user-supplied variables in affected versions prior to 27.0.3 and 28.0.1, enabling a reflected cross-site scripting (XSS) attack (CWE-79) and arbitrary markdown file downloads (CWE-552). It has a CVSS v3.1 base score of 8.7 (AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N), indicating high severity due to network accessibility, low attack complexity, and significant impacts on confidentiality and integrity.
An attacker with low privileges (PR:L), such as an authenticated user, can exploit this by crafting a malicious link that tricks a victim into interacting with it (UI:R), such as clicking or submitting input. Successful exploitation leads to reflected XSS, allowing execution of arbitrary JavaScript in the victim's browser with elevated scope (S:C), potentially stealing session cookies, keystrokes, or other sensitive data. The same input vector also permits downloading arbitrary markdown files from the server, exposing potentially confidential research data or configurations.
The GitHub security advisory (GHSA-j2p3-58m2-v6q3) confirms the vulnerability is fixed in LORIS versions 27.0.3 and 28.0.1 through improved input sanitization in the help_editor module. Security practitioners should urge users of affected LORIS installations to upgrade immediately and review access controls to the help_editor module, as it requires low privileges for exploitation.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-20574
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 to before 27.0.3 and 28.0.1, the help_editor module of LORIS did not properly sanitize some user supplied variables which…
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could result in a reflected cross-site scripting attack if a user is tricked into following an invalid link. The same input vector could also allow an attacker to download arbitrary markdown files on an unpatched server. 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
V8.4.2V1.1.2V1.3.2
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.
Developer testing and evaluation can discover missing or incorrect input neutralization through targeted web-application tests.
Input validation directly enforces neutralization of untrusted data before it reaches web output generation.
Output filtering can catch or sanitize unneutralized script content before it is served to users.
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.
Secure SDLC practices directly target introduction of XSS via coding standards/testing (mostly), yet the single broad outcome leaves many specific neutralization vectors unaddressed (partial).
Enforcing least-privilege permissions and authorization policies directly prevents unauthorized file/directory exposure.
Data-at-rest protections such as encryption or ACLs reduce the impact of unintended file exposure.
Logical segmentation and access protections stop external parties from reaching files that should remain internal.
Hardened configuration baselines commonly include file-system permission settings that limit external access.
Patching and EOL replacement can remediate known XSS instances in libraries or frameworks (partial) but do nothing to enforce input neutralization in application code (none).
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.
Knowledge exchange on emerging attack techniques and patches reduces the likelihood that cross-site scripting flaws remain unaddressed in deployed applications.
Operational indicators of compromise for web-application attacks can be incorporated into WAF or input-filtering rules, lowering the likelihood that unsanitized data reaches the browser.
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.
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` (higher-evidence 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