CVE-2026-79781: rclone serve s3 Path Traversal via dot-dot object keys

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-25 · updated 2026-09-10
Weakness: CWE-22

Description

rclone serve s3 before 1.74.4 contains a path traversal vulnerability that allows attackers to read and overwrite root-level files by using dot-dot segments in S3 object keys. Attackers can send requests with object keys like ../root-secret.txt to escape the bucket namespace and access files in the serve root directory.

Affected products

rclone: before 1.74.4 — fixed in 1.74.4

How to fix

Upgrade to a fixed version: rclone 1.74.4. Check the vendor advisory for mitigations.

References

https://github.com/rclone/rclone/security/advisories/GHSA-8v25-v8p6-qf7v
https://www.vulncheck.com/advisories/rclone-serve-s3-path-traversal-via-dot-dot-object-keys
https://github.com/rclone/rclone/security/advisories/GHSA-8v25-v8p6-qf7v

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