# CVE-2026-116196: Rclone B2 backend credential exposure on HTTP redirects

Source: https://junglewise.ai/threats/cve-2026-116196-rclone-before-v1-75-2-contains-a-credential-exposure  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-25. Updated: 2026-10-25  
License: CC BY 4.0 with a link back

CVE-2026-116196 · Severity: medium · CVSS 5.3 · Published 2026-10-25

Rclone is a file synchronization tool that can back up data to cloud storage services like Backblaze B2. When configured to use a custom download URL (commonly a CDN), Rclone may leak the live account authorization token and encryption keys if the CDN performs an HTTPS-to-HTTP downgrade redirect or redirects to another host. An attacker with network access could capture these credentials and gain full account access or decrypt encrypted data.

Technologies: [Rclone](https://junglewise.ai/threats/technologies/rclone). Vendors: [Rclone](https://junglewise.ai/threats/vendors/rclone).

## Quick answers

**Is CVE-2026-116196 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-116196 being exploited in the wild.

**How severe is CVE-2026-116196?** Medium severity, with a CVSS score of 5.3, published 25 October 2026.

**Which products and versions are affected?** Rclone before v1.75.2.

**Is there a fix for CVE-2026-116196?** Yes: fixed in v1.75.2. Until then: Ensure --b2-download-url (if set) always uses an explicit https:// scheme and that the fronting CDN or proxy never issues plaintext HTTP redirects. Avoid pointing download URLs at third-party infrastructure unless you control the redirect policies.</anigation>
<parameter name="timeline">[{"kind":"disclosed","at":"2026-10-09"},{"kind":"advisory","at":"2026-10-25"}] Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-116196 attacked?** It is attacked over the network or from the adjacent network, in a software library.

**Am I affected by CVE-2026-116196?** Check whether you run Rclone at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in v1.75.2

Ensure --b2-download-url (if set) always uses an explicit https:// scheme and that the fronting CDN or proxy never issues plaintext HTTP redirects. Avoid pointing download URLs at third-party infrastructure unless you control the redirect policies.</anigation>
<parameter name="timeline">[{"kind":"disclosed","at":"2026-10-09"},{"kind":"advisory","at":"2026-10-25"}]

## Technical details

The vulnerability occurs in the B2 backend's getOrHead function, which sends requests with permanent Authorization headers and SSE-C encryption key headers. When --b2-download-url is set, Go's default HTTP client forwards the Authorization header on same-host redirects regardless of scheme downgrade (HTTPS to HTTP), and forwards custom SSE-C headers to any redirect target including different hosts. An adjacent-network attacker can capture cleartext credentials or encryption keys from redirect chains.

## Affected products

- Rclone Rclone before v1.75.2

## References

- [https://github.com/rclone/rclone/security/advisories/GHSA-gpw7-77cq-9f72](https://github.com/rclone/rclone/security/advisories/GHSA-gpw7-77cq-9f72)
- [https://www.vulncheck.com/advisories/rclone-before-1.75.2-b2-credential-leak-on-redirect-via-b2-download-url](https://www.vulncheck.com/advisories/rclone-before-1.75.2-b2-credential-leak-on-redirect-via-b2-download-url)

## Related threats

- [Rclone path traversal in translateLink function](https://junglewise.ai/threats/cve-2026-116195-rclone-before-1-75-2-contains-a-path-traversal-vulnerability-in)
- [Rclone cross-site request forgery in pCloud OAuth callback](https://junglewise.ai/threats/cve-2026-116194-rclone-from-1-52-0-before-1-75-2-contains-a-cross-site-request)
- [Rclone serve webdav authentication bypass via OPTIONS requests](https://junglewise.ai/threats/cve-2026-116193-rclone-from-1-64-0-before-1-75-2-contains-an-authentication)
- [rclone server-side request forgery via --rc-serve scheme-relative roots](https://junglewise.ai/threats/cve-2026-116192-rclone-from-1-37-before-1-74-2-contains-a-server-side-request)
- [rclone selfupdate signature verification bypass in SHA256SUMS](https://junglewise.ai/threats/cve-2026-116189-rclone-from-1-55-0-before-1-75-2-contains-a-signature)