Critical severity · published Sep 10, 2026
CVE-2026-88044
rclone: RC per-server auth-proxy bypass
9.1
CVSS
0.5%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 42% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RC
rclone · rclone
>= 1.70.0, < 1.75.1 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-88044
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-88044
github.com
https://github.com/rclone/rclone/commit/739403963abf6f58003c2becd5f7c4ad0d644153
github.com
https://github.com/rclone/rclone/releases/tag/v1.75.1
github.com
https://github.com/rclone/rclone/security/advisories/GHSA-p569-5gjg-9cmj
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