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Vulnerability · Published Sep 10, 2026 · Assigned by GitHub_M

CVE-2026-88017rclone: FTP cross-session auth-proxy backend confusion

High 7.3

In plain English

A high-severity security flaw in rclone from rclone. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 14% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.3High
Exploit odds (30 days)0.2%top 85.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

rclone is a command-line program to sync files and directories to and from different cloud storage providers. From 1.64.0 until 1.75.1, the FTP auth-proxy driver in cmd/serve/ftp/ftp.go stores one obscured password per username in the server-wide userPass map[string]string instead of binding the credential or VFS to the authenticated session. If two accepted credentials use the same username but resolve to different proxy backends, a later CheckPasswd login overwrites userPass[user], and subsequent getVFS operations on the first session are reauthorized with the later password. The first session can then read, create, overwrite, rename, or delete objects using the second credential’s backend authority. Exploitation requires the later same-username login to occur while the first session remains open. This issue is fixed in version 1.75.1.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12rcloneno fix listedDEBIAN-CVE-2026-88017
Debian:13rcloneno fix listedDEBIAN-CVE-2026-88017
Gogithub.com/rclone/rclone1.75.1GHSA-c476-6w5q-jw77
Gogithub.com/rclone/rclone1.75.1GO-2026-6458

Affected products (as reported)

VendorProductVersions
rclone rclone >= 1.64.0, < 1.75.1

Weakness: CWE-488 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

References