CVE-2026-116189

Rclone before v1.75.2 contains a credential exposure vulnerability in the b2 backend that leaks the live account Authorization token and SSE-C keys on HTTP redirects from --b2-download-url hosts. Attackers can observe a same-host HTTPS-to-HTTP downgrade redirect to capture the cleartext B2 token, or receive cross-host redirects disclosing SSE-C customer encryption keys.

Rclone before 1.75.2 contains a path traversal vulnerability in the local backend's translateLink function, which trims the .rclonelink suffix from a path after the containment check, so a name can resolve outside the destination root. Attackers can plant a directory named ...rclonelink in a source tree synced with --links and --metadata to change ownership, timestamps, and xattrs of the destination's parent directory.

Rclone from 1.52.0 before 1.75.2 contains a cross-site request forgery vulnerability in the pCloud backend's localhost OAuth callback, which disables the state check and trusts the hostname parameter. Malicious web pages can send a stateless request to port 53682 during authorization, planting attacker tokens and API hosts so later transfers reach the attacker.

Rclone from 1.64.0 before 1.75.2 contains an authentication bypass vulnerability in serve webdav that lets unauthenticated attackers skip authentication by sending OPTIONS requests. Attackers can probe arbitrary paths and compare Allow header values to determine whether files or collections exist, enabling namespace enumeration.

rclone from 1.37 before 1.74.2 contains a server-side request forgery vulnerability that allows unauthenticated attackers to redirect http and netstorage backend requests by supplying a double-slash root on an existing named remote via --rc-serve. Attackers can make HEAD/GET requests to attacker-chosen hosts to read responses, capture configured custom headers, or obtain valid NetStorage request signatures.

Rclone before 1.75.2 contains a path traversal vulnerability in serve webdav that allows unauthenticated attackers to write above the served root by sending an unvalidated '..' path component. Attackers can send MKCOL /.. to plant a VFS node, then PUT, MOVE, COPY, or MKCOL to create, overwrite, or delete files belonging to other tenants.

rclone from v1.56.0 before v1.75.2 contains an information disclosure vulnerability in the WebDAV backend that forwards operator-configured custom credential headers to different hosts on HTTP 3xx redirects. Attackers who control or influence a cross-host redirect can capture headers such as X-Auth-Token set via --webdav-headers and replay them against the original WebDAV service.

rclone serve s3 versions 1.75.0 before 1.75.2 contain an integer overflow vulnerability in multipart reorder-memory accounting that bypasses the configured buffer limit. Attackers can open two concurrent current-part PUT requests declaring huge lengths to wrap the signed int64 counter and retain out-of-order parts in memory, exhausting the host.

Rclone from v1.68.0 before v1.75.2 contains an authorization bypass vulnerability in serve s3 --auth-proxy that allows authenticated tenants to manipulate other tenants' multipart uploads by referencing their upload IDs. Attackers who learn a victim's bucket, object, and upload ID can inject parts, complete, or abort in-flight uploads and view upload and object metadata across tenants.

rclone is a command-line program to sync files and directories to and from different cloud storage providers. From 1.70.0 until 1.75.1, the serve/start RC interface accepts per-server proxyOpt.AuthProxy settings, and the FTP and S3 constructors in cmd/serve/ftp/ftp.go and cmd/serve/s3/server.go incorrectly check the process-global proxy.Opt.AuthProxy value instead. When the global value is empty, the request-local authentication proxy is ignored: FTP falls back to the fixed filesystem with username anonymous and any password, while S3 with AuthKey serves the fixed RC fs rather than the backend selected by the proxy. The dedicated command-line servers that configure the global option are not affected. This issue is fixed in version 1.75.1.