CyberSecBulletin
CVE-2026-88017NVD status: Analyzed

rclone: Exposure of Data Element to Wrong Session

Published Updated By the CyberSecBulletin desk

CVE-2026-88017 is a high-severity exposure of data element to wrong session vulnerability in rclone, with a CVSS 3.1 base score of 7.3 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, but only if a user takes part, for example by opening a link or file. Affected rclone versions: >= 1.64.0, < 1.75.1. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.23% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of rclone you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on github.com for workarounds and exact fixed builds.
  3. Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.

Affected products and versions

VendorProductAffected versionsFixed in
Rclonerclone>= 1.64.0, < 1.75.1Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
RequiredA user must take an action such as opening a file or link.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
NoneAvailability is not affected.

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N. Scored by CNA (github.com).

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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Exposure of Data Element to Wrong Session

The product does not sufficiently enforce boundaries between the states of different sessions, causing data to be provided to, or used by, the wrong session.

How developers prevent this class of flaw

  • Protect the application's sessions from information leakage. Make sure that a session's data is not used or visible by other sessions.
  • Use a static analysis tool to scan the code for information leakage vulnerabilities (e.g. Singleton Member Field).
  • In a multithreading environment, storing user data in Servlet member fields introduces a data access race condition. Do not use member fields to store information in the Servlet.

More Exposure of Data Element to Wrong Session vulnerabilities (CWE-488)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in rclone

All rclone vulnerabilities

Recent Exposure of Data Element to Wrong Session vulnerabilities

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