CVE-2026-88013: rclone: http backend forwards custom/auth headers to a different host on redirect
rclone is a command-line program to sync files and directories to and from different cloud storage providers. From 1.49.0 until 1.75.1, the HTTP backend attaches headers configured through --http-headers or headers= to requests in backend/http/http.go, while its fshttp.NewClient client follows redirects without a backend-specific http.Client.CheckRedirect policy. A configured remote that redirects to another host can therefore cause custom secrets such as X-Api-Key to be resent to that untrusted destination, and a same-host HTTPS-to-HTTP redirect can expose Authorization or Cookie headers in cleartext. Listing, stat, download, mount, and serve operations can trigger the leak during normal use. This issue is fixed in version 1.75.1.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
rclone http backendto a version that resolves this vulnerability.Fixed in 1.75.1
Event History
Frequently Asked Questions
Which deployments are exposed?
Deployments using rclone's HTTP backend from version 1.49.0 up to, but not including, 1.75.1 are affected when custom headers are configured through --http-headers or headers=. A remote must issue a redirect for the headers to be forwarded beyond the intended request destination.
What information can leak, and under what redirect conditions?
Custom secrets configured as headers, such as X-Api-Key, can be resent when the remote redirects to a different host. A redirect from HTTPS to HTTP on the same host can expose Authorization or Cookie headers in cleartext.
Which rclone activity can trigger the issue?
Normal HTTP backend operations including listing, stat, download, mount, and serve can follow a redirect and trigger the header leak.
What is the remediation?
Upgrade rclone to version 1.75.1, which fixes the issue.