Summary
rclone: Path traversal in serve s3 allows reading and overwriting root-level files
Impact
This is a path traversal / improper path normalization vulnerability in rclone serve s3.
An attacker who can send requests to an affected rclone serve s3 endpoint can use dot-dot object keys to read or overwrite files outside the selected bucket directory but still inside the configured serve root.
In deployments where rclone serve s3 exposes a root containing multiple buckets or root-level operational files, this can allow unauthorized disclosure or modification of files that are not intended to be accessible as objects in the selected bucket.
The issue is especially relevant when rclone serve s3 is run without --auth-key, because rclone documents that this configuration allows anonymous access. If authentication is configured, exploitation would require valid S3 access to the server.
Suggested fix:
Do not build backend paths by directly passing untrusted S3 object keys to path.Join with the bucket name.
Before accessing the backend, reject object keys containing path traversal segments that would escape the selected bucket after normalization. Alternatively, preserve object keys as opaque S3 names and encode path separators or dot-dot segments so they cannot affect backend path resolution.
Affected version tested:
rclone v1.74.3 official Windows binary
Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.
GHSA-8V25-V8P6-QF7V has a CVSS score of 6.5 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.74.4); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is GHSA-8V25-V8P6-QF7V? GHSA-8V25-V8P6-QF7V is a medium-severity path traversal vulnerability in github.com/rclone/rclone (go), affecting versions <= 1.74.3. It is fixed in 1.74.4. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
- How severe is GHSA-8V25-V8P6-QF7V? GHSA-8V25-V8P6-QF7V has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of github.com/rclone/rclone are affected by GHSA-8V25-V8P6-QF7V? github.com/rclone/rclone (go) versions <= 1.74.3 is affected.
- Is there a fix for GHSA-8V25-V8P6-QF7V? Yes. GHSA-8V25-V8P6-QF7V is fixed in 1.74.4. Upgrade to this version or later.
- Is GHSA-8V25-V8P6-QF7V exploitable, and should I be worried? Whether GHSA-8V25-V8P6-QF7V is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether GHSA-8V25-V8P6-QF7V is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix GHSA-8V25-V8P6-QF7V? Upgrade
github.com/rclone/rcloneto 1.74.4 or later.