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LorisApplication · Mcgill

CVE-2026-34985

MEDIUM · 6.5 CVSS v3.1 Published 2026-04-08
Fix available
A fix is available. Upgrade to after 27.0.2 or later.
See remediation →
71/100
Remediation priority · Elevated
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
LORIS (Longitudinal Online Research and Imaging System) is a self-hosted web application that provides data- and project-management for neuroimaging research. From 16.1.0 to before 27.0.3 and 28.0.1, While the frontend of the media module filters files that the user should not have access to, the backend was not applying access checks and it would be possible for someone who should not have access to a file to access it if they know the filename. This vulnerability is fixed in 27.0.3 and 28.0.1.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

LORIS media module suffers from an Insecure Direct Object Reference (IDOR) vulnerability where the backend does not perform server-side access validation, relying only on frontend filtering. An attacker with knowledge of a filename can access files they should not have permission to view.

MitigationUpgrade to LORIS version 27.0.3 or 28.0.1 which includes proper backend access control checks; alternatively, implement server-side authorization validation for all media file requests.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
LorisApplication
Affected:>= 16.1.0, <= 27.0.2= 28.0.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed LORIS version
    Locate the LORIS version file (typically at /loris/project/version or check the Git commit hash in the installation directory). Compare this version against the affected ranges: >= 16.1.0 through <= 27.0.2, or exactly version 28.0.0.
    Affected if The installed version falls within 16.1.0 to 27.0.2 inclusive, or is exactly 28.0.0
  2. Verify media module is enabled
    Check the LORIS configuration file (Config.xml or config.xml in the project directory) for the Media module entry under the available modules section. Confirm the module is set to 'true' or 'enabled'.
    Affected if The media module is enabled in the LORIS configuration
  3. Inspect media endpoint backend code for authorization
    Examine the backend handler for media file requests (typically in php/medianix/ or modules/media/ endpoint handlers). Look for permission checks or user session validation before serving file content. Search for functions like checkPermission, authorize, or session validation in the media download logic.
    Affected if The backend media handler lacks authorization checks before returning file content
  4. Review API access patterns for direct file requests
    Examine HTTP access logs for requests to the media API endpoint (commonly /media/ or /api/v0.4/media/) where filenames are passed as parameters. Check if these requests bypass any frontend permission filtering.
    Affected if Direct API requests with known filenames can be made to access files without backend permission validation

You are affected if running LORIS version 16.1.0 through 27.0.2 or exactly 28.0.0, the media module is enabled, and the backend does not perform authorization checks before serving media files.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 27.0.2
Interim mitigation

Upgrade to LORIS version 27.0.3 or 28.0.1 which includes proper backend access control checks; alternatively, implement server-side authorization validation for all media file requests.

Recommended fix High confidence

27.0.3 or 28.0.1 (depending on your major version branch)

  1. Identify your current LORIS version by checking the application or source code
  2. If running version 27.0.2 or earlier: upgrade to version 27.0.3
  3. If running version 28.0.0: upgrade to version 28.0.1
  4. After upgrade, verify the media module backend now properly enforces access controls

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Loris Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,640
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,224.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-34985 in production — separate from our analysis above.

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What this is

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What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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