Executive Summary

CVE-2026-35525 is a vulnerability in LiquidJS, a JavaScript template engine, where the software performs directory containment checks based on the pathname string rather than the actual resolved filesystem path (realpath). This means that if a symbolic link (symlink) is placed inside an allowed template directory pointing to a file outside that directory, LiquidJS will incorrectly allow access to and render the external file.

The issue arises because LiquidJS checks whether a file path is inside configured partials or layouts roots by examining the path string alone, without resolving symlinks. As a result, an attacker who can place or influence symlinks inside trusted template directories can cause LiquidJS to read and render files outside the intended safe directories.

This vulnerability affects the tags {% include %}, {% render %}, and {% layout %} in LiquidJS versions prior to 10.25.3 and is classified as a root restriction bypass via symlinked templates.

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Compliance Impact

This vulnerability allows attackers to read arbitrary files outside the designated template roots by exploiting symbolic link traversal, leading to unauthorized information disclosure.

Such unauthorized disclosure of sensitive or personal data could lead to non-compliance with data protection regulations and standards like GDPR or HIPAA, which mandate strict controls on access to protected information.

Therefore, if exploited, this vulnerability could result in violations of confidentiality requirements under these regulations, potentially causing legal and financial repercussions for affected organizations.

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Impact Analysis

This vulnerability allows attackers to read arbitrary files outside the designated template roots by exploiting symbolic link traversal. Because LiquidJS renders the contents of files pointed to by symlinks inside trusted directories, an attacker can gain unauthorized access to sensitive files on the filesystem.

The impact includes unauthorized information disclosure, which can expose secrets, configuration files, or other sensitive data that should not be accessible through the template engine.

The vulnerability requires no privileges or user interaction and can be exploited remotely with low complexity, making it a high-severity risk.

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Detection Guidance

This vulnerability can be detected by checking for the presence of symbolic links within the allowed partials or layouts directories that point to files outside these directories. Since the issue arises from LiquidJS following symlinks without verifying their real paths, identifying such symlinks is key.

You can use filesystem commands to find symlinks inside the template root directories and verify if they point outside the allowed roots.

• On Unix-like systems, use the command: find /path/to/partials_or_layouts -type l -exec ls -l {} \;
• Then, for each symlink found, check the real path it points to using: readlink -f /path/to/symlink

If any symlink points outside the allowed template root directories, it indicates a potential exploitation of this vulnerability.

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Mitigation Strategies

The immediate mitigation step is to upgrade LiquidJS to version 10.25.3 or later, where the vulnerability is fixed by performing realpath-based checks to prevent symlink traversal.

Until the upgrade is applied, you should audit and remove any symbolic links inside the partials or layouts directories that point outside the allowed roots to prevent unauthorized file access.

Additionally, restrict the ability of untrusted users or processes to create or modify files, including symlinks, within the trusted template directories.

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