rclone versions 1.56.0 through 1.75.0 contain a path traversal vulnerability in the `rclone serve docker` volume plugin. newVolume() in cmd/serve/docker/volume.go computes a volume's mountpoint as filepath.Join(drv.root, name) from the attacker-supplied `name` field of a Docker VolumeDriver.Create request without verifying that the result stays within drv.root (default /var/lib/docker-volumes/rclone), and checkMountpoint() then creates that directory with file.MkdirAll before mounting. A volume name containing enough `..` components (e.g. "../../../../../../etc") therefore resolves outside the base directory, allowing anyone able to submit a VolumeDriver.Create request to the plugin socket — normally the Docker daemon, or a workload that can request named volumes in a multi-tenant orchestration setup — to make the privileged rclone plugin process create a directory and mount a remote filesystem specified in the same request at an arbitrary host path, shadowing or disrupting system directories. The advisory notes Volume.restoreState() had the same missing validation when reloading persisted volume state. Fixed in 1.75.1.

rclone before 1.75.1 fails to confine names from server and third-party listing responses to the listed directory, allowing path traversal sequences in object names. Attackers can craft special names containing forward slashes and parent directory references to potentially write outside the destination root, though downstream protections in the local backend currently block actual file escape.

rclone before v1.75.0 contains a denial of service vulnerability in the WebDAV TUS creation handler that dereferences a nil response before checking for transport errors. A malicious or compromised configured endpoint can reset connections during TUS uploads to trigger a panic that terminates unrecovered goroutines and halts unrelated work in long-lived processes.

rclone before v1.75.0 fails to sanitize IBM IAM bearer tokens and SSE-C encryption keys during S3 redirect callbacks, allowing credentials to be preserved across scheme or host changes. Attackers observing network traffic from a trusted endpoint can capture reusable IBM IAM tokens on same-host HTTPS-to-HTTP downgrades or SSE-C keys on cross-origin redirects to access protected S3 objects.

rclone versions >= v1.72.0 and <= v1.74.4 (fixed in v1.75.0) contain multiple denial-of-service vulnerabilities in the archive backend's SquashFS parser, which relies on the github.com/diskfs/go-diskfs dependency. The parser fails to validate attacker-controlled superblock and metadata values before use. An attacker who can place or modify a SquashFS image in storage exposed through an rclone :archive: remote can craft a malicious image that triggers an integer division-by-zero panic (zero block size), an out-of-bounds slice panic (out-of-range inode metadata offset), or a non-progress CPU loop (truncated metadata stream). Variants 1 and 2 terminate the rclone process and, via 'rclone serve sftp', can crash the entire SFTP server; variant 3 causes sustained CPU consumption. Parsing is lazy, so a victim or remote client must address or descend into the malicious archive object to trigger it.

rclone versions before v1.75.0 fail to reject transport downgrades in redirect handling, allowing Basic authorization and Cookie headers to be replayed over plaintext HTTP after same-host HTTPS-to-HTTP redirects. An on-path attacker observing the plaintext hop can capture and reuse credentials to perform WebDAV operations with the compromised account's permissions.

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.

rclone before 1.74.4 fails to mask special permission bits when applying source-supplied mode metadata in the local backend, allowing attackers to set setuid/setgid bits on attacker-controlled files. When copying with metadata preservation from an untrusted remote, attackers can plant a setuid binary that escalates privileges to root if rclone runs as root, or to the service account user otherwise.

rclone before 1.75.0 mounts the pprof debug handler as its own router route, bypassing the fail-closed authentication rule in the main handler. Attackers can access the /debug/pprof/cmdline endpoint unauthenticated to retrieve the full process argv including backend credentials.

rclone before v1.75.0 includes full Go stack traces in RC API error responses when panics occur. Attackers can trigger panics to leak internal file paths, module versions, goroutine states, and memory addresses.