Canonical EUVD-2026-20594

Attacker must place a symlink inside the configured partials or layouts directory of a LiquidJS application. The symlink must point outside that directory. Victim's LiquidJS template must load the symlink via {% include %}, {% render %}, or {% layout %} tags. Requires ability to write files to the partials/layouts directory.

Real-world risk is moderate and highly context-dependent. Without CVSS vector data, assessment relies on impact analysis and deployment patterns. The vulnerability requires authenticated access to create symlinks within template directories, significantly limiting attack surface compared to unauthenticated remote exploits. SSVC technical impact is partial (information disclosure only, no code execution or data modification). Exploitation is not automatable as it requires specific filesystem access and knowledge of target file paths. Primary risk scenarios include multi-tenant CMS platforms where users upload themes, collaborative template repositories where contributors have filesystem access, or containerized environments with mounted volumes. In hardened production deployments with read-only template directories and strict filesystem permissions, exploitability is minimal. The availability of public POC code demonstrates feasibility but the authentication and filesystem access prerequisites prevent widespread exploitation. Organizations using LiquidJS with untrusted template sources should prioritize patching, while those with strictly controlled template directories face lower immediate risk. The canonical path resolution issue is a common oversight in filesystem security controls, making this a valuable case study for secure file handling patterns.

An attacker with contributor access to a multi-tenant blogging platform uploads a custom theme package containing a malicious symlink in the partials directory. The symlink named evil.liquid points to /etc/passwd on the host system. When administrators preview the theme or the template is rendered, LiquidJS processes {% render "evil.liquid" %} and validates that partials/evil.liquid falls within the allowed template root. Since validation occurs on the symlink path rather than the target, the check passes. The filesystem then follows the symlink during file read operations, causing LiquidJS to render the contents of /etc/passwd into the template output. The attacker exfiltrates sensitive system information including user accounts and configuration details through the rendered page content. Publicly available exploit code exists demonstrating the technique with minimal complexity.