rclone is a command-line program to sync files and directories to and from different cloud storage providers. Prior to 1.75.0, the shared HTTP CONNECT helper in lib/proxy/http.go parses proxy CONNECT responses with http.ReadResponse over an unrestricted buffered reader, allowing a malicious or compromised configured proxy, or an active on-path actor controlling a plaintext HTTP proxy hop, to send oversized headers that grow memory until the rclone process fails. The affected helper is used by FTP and SFTP proxy connections, and SFTP reaches the parser before SSH server authentication, so target host key validation does not constrain a malicious proxy. This issue is fixed in 1.75.0.

rclone is a command-line program to sync files and directories to and from different cloud storage providers. Prior to 1.75.0, a valid but nondefault FTP filename encoding in backend/ftp/ftp.go can restore raw CR/LF immediately before an attacker-controlled path is interpolated into the line-oriented FTP control channel, and github.com/jlaffaye/ftp formats the argument through textproto.Conn.Cmd without rejecting CR or LF, allowing a filename such as victim CRLF DELE other-secret CRLF NOOP to inject an independent authenticated FTP command when the victim copies or syncs to a more-privileged FTP destination. This issue is fixed in 1.75.0.

rclone is a command-line program to sync files and directories to and from different cloud storage providers. Prior to v1.75.0, rclone interpolates remote SFTP paths into PowerShell hash commands in backend/sftp/sftp.go, and quoteOrEscapeShellPath escapes only ASCII apostrophe even though PowerShell treats U+2018, U+2019, U+201A, and U+201B as single-quote delimiters, allowing an attacker-controlled filename to terminate the intended path literal and append PowerShell statements that execute as the victim SSH account when server-side hashing is invoked. This issue is fixed in v1.75.0.

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.