rclone: http backend forwards custom/auth headers to a different host on redirect

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

3.7 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS

• CVE-2026-88013: 0.19% estimated exploitation activity in the next 30 days; percentile 8.35 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Vulnerability Details File: backend/http/http.go Lines: 285 (client construction — no CheckRedirect), 505-510 (addHeaders, writes configured secret headers onto every request), 533-534 / 700-701 / 782-785 (f.httpClient.Do(req) used by List/stat/download) Root Cause The http backend lets a user attach arbitrary secret headers to every request via --http-headers/headers= (documented for authentication: '"Cookie","name=value","Authorization","xxx"'). The backend's HTTP client is built with fshttp.NewClient(ctx), which never sets http.Client.CheckRedirect, so it falls back to Go's stdlib default redirect policy. Go's default policy only strips four header names (Authorization, Www-Authenticate, Cookie, Cookie2), and only when the redirect target's host differs from the original — every other configured header is copied to the redirect target unconditionally, regardless of host or scheme. Even the four protected names survive a same-host https:// → http:// downgrade, since Go only checks…

Published by the source

10 Sep 2026, 23:02 UTC

Last modified by the source

19 Sep 2026, 09:25 UTC

Source last checked

26 Oct 2026, 15:29 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-486v-q2wf-fp2r

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GO-2026-6463

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-486v-q2wf-fp2r

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# Patch Next advisory brief: CVE-2026-88013

Advisory: rclone: http backend forwards custom/auth headers to a different host on redirect
IDs: CVE-2026-88013, GHSA-486v-q2wf-fp2r
Record: https://patchnext.com/advisories/cve-2026-88013 (revision 3, source checked 26 Oct 2026, 15:29 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 3.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/rclone/rclone 1.75.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/rclone/rclone: affected >= 1.49.0, <= 1.75.0; fixed in 1.75.1

## Suggested inspection (read-only)
- Go github.com/rclone/rclone: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/rclone/rclone.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-486v-q2wf-fp2r (OSV record GHSA-486v-q2wf-fp2r lists affected ranges: Go github.com/rclone/rclone >=1.49.0 <1.75.1 (fixed))
- Verified: https://osv.dev/vulnerability/GO-2026-6463 (OSV record GO-2026-6463 lists affected ranges: Go github.com/rclone/rclone >=1.49.0 <1.75.1 (fixed))
- Verified: https://github.com/advisories/GHSA-486v-q2wf-fp2r (GitHub-reviewed advisory GHSA-486v-q2wf-fp2r lists affected ranges: Go github.com/rclone/rclone >=1.49.0 <=1.75.0)

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