---
title: "CVE-2026-88044: rclone: RC per-server auth-proxy bypass"
url: https://erroneo.us/security/cve/CVE-2026-88044/
description: "CVE-2026-88044 (github.com/rclone/rclone (Go)): rclone is a command-line program to sync files and directories to and from different cloud storage…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-09-10
date_modified: 2026-09-10
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-88044"
kev: false
cvss: 9.1
epss: 0.00492
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-88044: rclone: RC per-server auth-proxy bypass

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.5% , percentile 41: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 41% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes github.com/rclone/rclone (Go) >= 1.70.0, < 1.75.1, fixed in 1.75.1 . Check your lockfile, including transitive dependencies.

## What it is

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.

## Affected packages

- Go `github.com/rclone/rclone` >= 1.70.0, < 1.75.1 → fixed: 1.75.1

## Affected products (CVE record)

- rclone rclone: >= 1.70.0, < 1.75.1

## Severity

- GitHub_M CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`
- GitHub CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.49% probability of exploitation activity in the next 30 days; percentile 41.

## Sources

- [GitHub Advisory GHSA-p569-5gjg-9cmj](https://github.com/advisories/GHSA-p569-5gjg-9cmj)
- [CVE.org record CVE-2026-88044](https://www.cve.org/CVERecord?id=CVE-2026-88044)
- [NVD entry CVE-2026-88044](https://nvd.nist.gov/vuln/detail/CVE-2026-88044)
- [github.com](https://github.com/rclone/rclone/security/advisories/GHSA-p569-5gjg-9cmj)
- [github.com](https://github.com/rclone/rclone/commit/739403963abf6f58003c2becd5f7c4ad0d644153)
- [github.com](https://github.com/rclone/rclone/releases/tag/v1.75.1)

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Source page: https://erroneo.us/security/cve/CVE-2026-88044/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt