CVE-2026-71313 in Rclone
Summary
by MITRE • 08/06/2026
rclone is a command-line program to sync files and directories to and from different cloud storage providers. From v1.51.0 until v1.75.0, the local backend in backend/local/local.go relies on the configurable filename encoder to prevent remote filename data from becoming operating-system path syntax, so a local destination using Slash, None, Raw, or on Windows an encoding that preserves backslash can decode a standard-encoded fullwidth dot-dot component or native backslash form into an actual parent-directory component before filepath.Join resolves it outside the configured local root, allowing an attacker-controlled source object to create or overwrite files outside the selected destination directory as the rclone process. This issue is fixed in v1.75.0.
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Analysis
by VulDB Data Team • 08/06/2026
The vulnerability in rclone affects versions between 1.51.0 and 1.75.0, specifically within the local backend implementation located in backend/local/local.go. This flaw represents a path traversal attack vector that exploits the filename encoding configuration to bypass directory restrictions. The vulnerability stems from insufficient validation of remote filename components before they are processed into local filesystem paths, creating an opportunity for attackers to manipulate file paths and escape the intended destination directory.
The technical mechanism involves the configurable filename encoder which is designed to prevent remote filename data from conflicting with operating system path syntax. However, when using certain encoding schemes such as Slash, None, Raw, or on Windows systems with backslash-preserving encodings, the software fails to properly sanitize fullwidth dot-dot components or native backslash forms. These encoded sequences can be decoded into actual parent directory references before filepath.Join resolves them outside the configured local root directory. This creates a scenario where attacker-controlled source objects can manipulate the path resolution process to target files outside the designated destination directory.
The operational impact of this vulnerability is significant as it allows for arbitrary file creation and overwrites in directories accessible to the rclone process. An attacker could potentially leverage this to write malicious files to system directories, overwrite critical configuration files, or access sensitive data that should be restricted by the intended directory boundaries. The vulnerability affects any rclone operation that involves syncing files to local destinations where the filename encoding settings are configured to preserve certain path characters without proper sanitization.
This issue aligns with CWE-22 Path Traversal and follows patterns consistent with ATT&CK technique T1059 Command and Scripting Interpreter by enabling malicious file operations through compromised or manipulated file paths. The vulnerability demonstrates a classic insufficient input validation problem where remote data is not properly sanitized before being used in local filesystem operations. Organizations using rclone in environments where it processes untrusted source data must be particularly concerned about this vulnerability, as it could allow privilege escalation or data exfiltration attacks.
The fix implemented in version 1.75.0 addresses the core issue by introducing proper validation and sanitization of filename components before they are processed into local filesystem paths. This mitigation ensures that encoded parent directory references are properly neutralized regardless of the configured encoding scheme, preventing attackers from exploiting the path traversal mechanism to escape the intended destination directory boundaries. The update represents a defensive programming approach that validates all potential path components against the configured root directory to maintain proper isolation between different operational contexts.