CVE-2026-88044Network attack vector

Unauthorized backend access via ignored auth proxy

Published Sep 10, 2026 · Updated Sep 10, 2026

Authentication bypass in rclone 1.70.0 through 1.75.0 allows remote attackers to access FTP or S3 data through RC-started servers. The FTP and S3 constructors test the process-global proxy.Opt.AuthProxy value instead of each server's proxyOpt.AuthProxy, so they ignore the requested authentication proxy when the global value is empty. Exposure requires a server launched through serve/start with a per-server authentication proxy; FTP then accepts anonymous with any password, while S3 serves the fixed RC filesystem.

CVSS severityUnavailable
Unscored
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in rclone 1.70.0 through 1.75.0 allows remote attackers to access FTP or S3 data through RC-started servers. The FTP and S3 constructors test the process-global proxy.Opt.AuthProxy value instead of each server's proxyOpt.AuthProxy, so they ignore the requested authentication proxy when the global value is empty. Exposure requires a server launched through serve/start with a per-server authentication proxy; FTP then accepts anonymous with any password, while S3 serves the fixed RC filesystem.

The record

CVE
CVE-2026-88044
Published
Sep 10, 2026
Updated
Sep 10, 2026
Vendor
Rclone
Product
rclone
Classifications
T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 1.70.0, < 1.75.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Rclone · rcloneversion=>= 1.70.0, < 1.75.1

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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