EUVD-2026-75567
GHSA-486v-q2wf-fp2r
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessOperator configures rclone HTTP remote with secret headers
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DeliveryAttacker controls or compromises the remote server
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ExploitVictim rclone performs listing or download operation
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ExecutionRemote issues cross-host redirect
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Persistrclone forwards headers verbatim to attacker host
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ImpactAttacker captures leaked credentials
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V14 - Data Protection Data exposure prevention
MITRE ATT&CK
2 techniques across 2 tactics: Collection, Discovery The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | Exploitation requires two concurrent conditions: (1) the rclone HTTP backend remote must have at least one custom header configured (--http-headers or headers= containing a sensitive value such as Authorization, Cookie, or X-Api-Key), and (2) the configured remote server must issue either a cross-host redirect (302/301 to a different hostname or port) or a same-host HTTPS-to-HTTP downgrade redirect. The HTTP backend type (type=http) must be in use; no other rclone backends are affected. Exploitation is limited by the need to control or compromise the remote server's redirect behavior, or to achieve MITM positioning against HTTPS sessions. Rclone deployments using the HTTP backend without custom headers are completely unaffected, as the CheckRedirect fix in v1.75.1 is only applied when headers are present. |
| Impact | The CVSS 3.7 score (AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N) accurately reflects a narrow but real exposure. AC:H captures the compound preconditions: the victim must have sensitive headers configured AND must be pointing rclone at a remote that issues a cross-host or HTTPS-to-HTTP redirect. There is no CISA KEV entry and no EPSS score was provided in the source data; the absence of public exploit code and the specificity of the attack path suggest this is a low-to-medium operational priority outside of automated pipelines using third-party HTTP remotes with credentials. The primary at-risk population is CI/CD workflows and scripts that sync from semi-trusted HTTP sources using API tokens or session cookies. Impact is limited to credential leakage (C:L) with no integrity or availability consequence. The CVSS score is consistent with the described impact and no significant discrepancies exist between available signals. |
| Exploit ScenarioDerived | An operator configures rclone with an HTTP backend remote pointing to a third-party file mirror, supplying an X-Api-Key or Authorization header for authenticated access. The mirror's web server - under attacker control or compromised - responds to rclone's listing or download request with a 302 redirect to an attacker-controlled subdomain. Because no CheckRedirect policy exists in affected versions, rclone's HTTP client faithfully forwards the configured Authorization header to the attacker's server, where it is logged. No public exploit code has been identified; the attack requires either control of the redirect destination or MITM positioning on the network path. |
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Alert meAnalysisAIv1 – Sep 10, 2026
rclone's HTTP backend (versions 1.49.0-1.75.0) leaks user-configured secret headers - including Authorization, Cookie, and X-Api-Key values - to untrusted redirect destinations because the underlying Go HTTP client follows redirects without a CheckRedirect policy that strips sensitive headers at host boundaries. When a configured HTTP remote issues a cross-host redirect, net/http copies the original headers verbatim to the new destination; a same-host HTTPS-to-HTTP redirect similarly exposes those headers in cleartext. Listing, stat, download, mount, and serve operations can all trigger the leak during normal use. No public exploit has been identified at time of analysis and the issue is not listed in CISA KEV.
RemediationAI
Vendor-released patch: version 1.75.1, available at https://github.com/rclone/rclone/releases/tag/v1.75.1. Operators should upgrade to v1.75.1 or later, which introduces a CheckRedirect policy that strips configured headers on any cross-host redirect and refuses HTTPS-to-HTTP downgrade redirects when headers are present; the fix is confirmed by commits 22859b7e, 79fbc084, and 925fb4fb. If immediate upgrade is not possible, a compensating control is to avoid placing sensitive credentials in the headers= or --http-headers option for HTTP remotes whose redirect behavior is not fully under operator control; alternatively, restrict HTTP backend remotes to endpoints known not to issue cross-domain redirects. Note that removing credentials from the header configuration eliminates the vulnerability entirely (the CheckRedirect policy is only applied when headers are configured), at the cost of losing authenticated access to the remote.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 2 packages in go, euvd
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
The vulnerability originates in backend/http/http.go, where rclone attaches all headers configured via --http-headers or headers= to outgoing HTTP requests. The fshttp.NewClient Go HTTP client used for these requests follows redirects under net/http's default behavior, which copies the full header set from the original request to every subsequent redirect hop - regardless of destination host. No backend-specific http.Client.CheckRedirect policy was set prior to v1.75.1, so rclone had no mechanism to strip credentials when a redirect left the original host or downgraded from HTTPS to HTTP. CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor) accurately identifies the root cause: the absence of redirect-aware header sanitization allows configuration-supplied secrets to reach unauthorized third-party destinations. The fix introduces a checkRedirect function that strips configured headers on any cross-host redirect hop and refuses HTTPS-to-HTTP downgrades outright when headers are present.
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
AC:H reflects the compound requirement of custom headers plus redirect-issuing remote; impact is limited to credential leakage with no integrity or availability consequence.
Primary rating from Vendor (GitHub_M).
CVSS VectorNVD
Lifecycle Timeline
3DescriptionNVD
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.
Threat Intelligence Overview
NVD
CVE.org
EPSS
Vulnrichment
VulDB
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.
Authentication bypass in rclone's S3 server mode (rclone serve s3) allows any unauthenticated network attacker to impers
PowerShell smart-quote filename injection in rclone's SFTP backend allows an attacker who controls remote filenames to e
An issue was discovered in Rclone before 1.53.3. Rated high severity (CVSS 7.5), this vulnerability is remotely exploita
Cross-session credential isolation failure in rclone's FTP auth-proxy driver (versions 1.64.0-1.75.0) allows an authenti
Symlink escape in rclone's local backend (prior to v1.75.1) allows an attacker who controls sync source contents to appl
FTP CRLF injection in rclone before 1.75.0 allows an attacker who can place crafted filenames in a source namespace to i
Path traversal (Zip Slip class) in rclone's archive ZIP backend permits arbitrary file writes outside the intended desti
Denial of service in rclone prior to 1.75.1 allows unauthenticated remote attackers to crash individual HTTP or WebDAV c
Path traversal in rclone prior to 1.75.1 allows an attacker who can populate a source object store with raw `..` key seg
Cleartext disclosure of AWS STS session tokens affects rclone before 1.74.4 when its S3 backend follows a redirect that
Authentication/authorization bypass in rclone's dynamic serve interface (versions 1.70.0 through 1.75.0) lets remote att
Path traversal in the `rclone serve restic --private-repos` REST server (versions prior to 1.74.4) allows an authenticat
Exploit-DB