CVE-2026-26985: LORIS Path Traversal Vulnerability

CVE-2026-26985 Overview

CVE-2026-26985 is a path traversal vulnerability affecting LORIS (Longitudinal Online Research and Imaging System), a self-hosted web application designed for data and project management in neuroimaging research. This vulnerability allows authenticated users with appropriate authorization to exploit a directory traversal flaw to read configuration files on the server, some of which contain hard-coded credentials that could be leveraged for further compromise.

Critical Impact

Authenticated attackers can read sensitive configuration files containing hard-coded credentials, potentially enabling database access or lateral movement to other services if credentials are reused.

Affected Products

• LORIS versions 24.0.0 through 26.0.4
• LORIS versions 27.0.0 through 27.0.1
• LORIS versions prior to 28.0.0

Discovery Timeline

• 2026-02-25 - CVE-2026-26985 published to NVD
• 2026-02-25 - Last updated in NVD database

Technical Details for CVE-2026-26985

Vulnerability Analysis

This vulnerability is classified as CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), commonly known as path traversal or directory traversal. The flaw exists within the LORIS application's file handling mechanism, specifically in the electrophysiology browser module.

The vulnerability enables an authenticated attacker to manipulate file path inputs to traverse outside the intended directory structure and access arbitrary files on the server. The primary risk lies in the exposure of configuration files that contain hard-coded credentials. Since LORIS is open-source with publicly available code, attackers can easily identify the exact file paths and structures to target, significantly lowering the barrier to exploitation.

The impact is primarily on confidentiality and integrity, as exposed credentials could allow attackers to authenticate directly to backend databases or other integrated services. This could lead to unauthorized data access, modification, or exfiltration of sensitive neuroimaging research data.

Root Cause

The root cause stems from insufficient input validation and path sanitization in the file retrieval functionality within the electrophysiology browser module. The application fails to properly canonicalize and validate user-supplied path components before using them in file system operations. This allows attackers to use path traversal sequences (such as ../) to escape the intended directory and access files elsewhere on the server.

Additionally, the presence of hard-coded credentials in configuration files compounds the severity, as these static secrets cannot be easily rotated without application updates.

Attack Vector

The attack requires network access and authentication with specific permissions within the LORIS application. An attacker must first obtain valid credentials and the necessary authorization level to access the electrophysiology browser module.

Once authenticated, the attacker crafts malicious requests containing path traversal sequences targeting known configuration file locations. Given that LORIS is open-source, attackers can reference the public source code to identify exact file paths for configuration files containing credentials.

The attack flow proceeds as follows: the attacker authenticates to the LORIS application, accesses the vulnerable electrophysiology browser functionality, injects path traversal sequences into file path parameters, and retrieves configuration files containing hard-coded credentials. These credentials can then be used to access databases or other services where the credentials may be reused.

Detection Methods for CVE-2026-26985

Indicators of Compromise

• Unusual file access patterns in web server logs showing path traversal sequences (../, ..%2f, ..%252f)
• Access attempts to configuration files such as config.xml, database.ini, or similar outside normal application directories
• Authentication events from unexpected IP addresses following configuration file access
• Database connection attempts using credentials that should only exist in server-side configuration files

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block path traversal patterns in request parameters
• Monitor application logs for requests containing encoded traversal sequences targeting file retrieval endpoints
• Deploy file integrity monitoring on sensitive configuration directories to detect unauthorized access
• Analyze authentication logs for anomalous login patterns that may indicate credential theft

Monitoring Recommendations

• Enable verbose logging for the electrophysiology browser module and file access operations
• Configure alerting for failed and successful authentication attempts from new or unusual sources
• Implement database query auditing to detect unauthorized access using potentially compromised credentials
• Review access logs regularly for patterns consistent with credential enumeration or lateral movement

How to Mitigate CVE-2026-26985

Immediate Actions Required

• Upgrade LORIS to version 26.0.5, 27.0.2, or 28.0.0 or later immediately
• Rotate all credentials stored in configuration files that may have been exposed
• Review database and service access logs for unauthorized activity
• Audit user accounts with permissions to access the electrophysiology browser module

Patch Information

This vulnerability has been addressed in LORIS versions 26.0.5, 27.0.2, and 28.0.0. Organizations should update to these patched versions as soon as possible. Detailed release information is available in the LORIS v26.0.5 Release Notes, LORIS v27.0.2 Release Notes, and the GitHub Security Advisory GHSA-g3pp-rqvq-xxhp.

Workarounds

• Disable the electrophysiology browser module using the LORIS module manager until patching is complete
• Implement network segmentation to restrict access to LORIS instances from untrusted networks
• Deploy web application firewall rules to block requests containing path traversal patterns
• Review and restrict user permissions to minimize the number of accounts that can access vulnerable functionality

# Disable the electrophysiology_browser module via LORIS admin panel
# Navigate to: Admin > Module Manager > electrophysiology_browser > Disable

# Alternative: Restrict access via web server configuration (Apache example)
<Location "/electrophysiology_browser">
    Order deny,allow
    Deny from all
    # Allow only from specific trusted IPs during remediation
    Allow from 10.0.0.0/8
</Location>