Symlink Escape Vulnerability in Rclone Prior to 1.74.4

Executive Summary

CVE-2026-54572 is a vulnerability in Rclone, a command-line program used to sync files and directories with cloud storage providers. When the -l or --links flag is used, Rclone serializes symlinks as .rclonelink text objects and recreates them on a local destination.

The vulnerability occurs because Rclone does not validate the target of the symlink before recreating it. This allows an attacker to craft a malicious remote storage location containing an escaping symlink. When Rclone processes this symlink, a subsequent object write operation could place files outside the intended destination directory with attacker-chosen contents.

This issue has been fixed in Rclone version 1.74.4.

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Detection Guidance

Detecting this vulnerability involves checking if you are using a vulnerable version of Rclone (prior to 1.74.4) and if the -l/--links flag is enabled during sync operations. Since the vulnerability arises from improper symlink handling, you can inspect your system for suspicious symlinks or unexpected file writes outside intended directories.

• Check the installed version of Rclone by running: rclone version
• Review Rclone command logs or scripts for usage of the -l or --links flag, which is required for the vulnerability to be exploitable.
• Inspect destination directories for unexpected .rclonelink files or symlinks pointing outside the intended sync location.
• Monitor file system changes during Rclone operations to detect unauthorized writes outside the target directory.

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Impact Analysis

This vulnerability can impact you in several ways if you use Rclone with the -l or --links flag to sync files from an untrusted or attacker-controlled remote storage location:

• An attacker could plant a malicious symlink in the remote storage, causing Rclone to write files outside the intended destination directory on your local system.
• The attacker-chosen files could overwrite sensitive files on your system, leading to data corruption or loss.
• If the attacker writes executable files or scripts, they could achieve arbitrary code execution on your system, potentially leading to full system compromise.
• The vulnerability could be used to exfiltrate sensitive data by redirecting file writes to locations where the attacker can access them.

The impact is particularly severe if Rclone is run with elevated privileges, as the attacker could then write files to system directories.

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Compliance Impact

This vulnerability can affect compliance with common standards and regulations in the following ways:

• GDPR (General Data Protection Regulation): If the vulnerability leads to unauthorized access or exfiltration of personal data, it could result in a data breach. GDPR requires organizations to implement appropriate security measures to protect personal data, and failure to do so could lead to significant fines and legal consequences.
• HIPAA (Health Insurance Portability and Accountability Act): For organizations handling protected health information (PHI), this vulnerability could lead to unauthorized access or disclosure of PHI. HIPAA requires safeguards to ensure the confidentiality, integrity, and availability of PHI, and a breach could result in penalties and mandatory corrective actions.
• Other standards like ISO 27001, NIST, or PCI DSS: These standards require organizations to maintain the integrity and security of data. A vulnerability that allows unauthorized file writes or code execution could violate these requirements, leading to non-compliance and potential auditing or certification issues.

To maintain compliance, organizations should update Rclone to version 1.74.4 or later and ensure that they are not using the -l or --links flag with untrusted remote storage locations.

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Mitigation Strategies

To mitigate this vulnerability, follow these steps:

• Upgrade Rclone to version 1.74.4 or later, as the issue is fixed in this release.
• Avoid using the -l or --links flag when syncing untrusted remote sources, as this flag is required for the vulnerability to be exploited.
• If symlink support is necessary, ensure the remote source is trusted and validate symlink targets manually before syncing.
• Restrict write permissions on destination directories to minimize the impact of unauthorized file writes.
• Monitor sync operations for unexpected behavior, such as files being written outside the intended directory.

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