# CVE-2026-71310: rclone memory exhaustion via unbounded HTTP CONNECT response headers

Source: https://junglewise.ai/threats/cve-2026-71310-rclone-memory-exhaustion-via-unbounded-http-connect-response  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-05. Updated: 2026-08-05  
License: CC BY 4.0 with a link back

CVE-2026-71310 · Severity: medium · CVSS 5.9 · Published 2026-08-05

rclone is a command-line program used to manage and sync files on various cloud storage providers. A vulnerability in how it handles proxy connections allows a malicious or compromised proxy server to send an unlimited amount of data during the initial connection phase. This can cause rclone to consume all available system memory, leading to a crash that disrupts file transfers and other active operations.

Technologies: [github.com/rclone/rclone (Go)](https://junglewise.ai/threats/technologies/github-com-rclone-rclone), [Rclone](https://junglewise.ai/threats/technologies/rclone). Vendors: [Go](https://junglewise.ai/threats/vendors/go), [Rclone](https://junglewise.ai/threats/vendors/rclone).

## Quick answers

**Is CVE-2026-71310 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-71310 being exploited in the wild.

**How severe is CVE-2026-71310?** Medium severity, with a CVSS score of 5.9, published 5 August 2026.

**Which products and versions are affected?** github.com/rclone/rclone (Go) <= 1.74.0, SEMVER:introduced=0,fixed=1.75.0; Rclone <= 1.74.0.

**Is there a fix for CVE-2026-71310?** Yes. github.com/rclone/rclone (Go): upgrade to 1.75.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-71310 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-71310?** Check whether you run github.com/rclone/rclone (Go) or 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

- github.com/rclone/rclone (Go): upgrade to 1.75.0 or later

  ```sh
  go get github.com/rclone/rclone@v1.75.0
  ```


## Technical details

The vulnerability exists in the `HTTPConnectDial` helper within `lib/proxy/http.go`, which uses `http.ReadResponse` over an unrestricted buffered reader. Unlike standard HTTP transports, this implementation does not enforce a `MaxResponseHeaderBytes` limit or a handshake deadline. A malicious proxy or an on-path attacker (in plaintext scenarios) can send extremely large HTTP CONNECT response headers, leading to process-wide memory exhaustion (OOM). This affects backends that utilize this helper, such as SFTP and FTP. The issue is addressed in version 1.75.0 by enforcing a budget on CONNECT status and header sizes.

## Affected products

- rclone rclone <= 1.74.0

## Identifiers

- CVE-2026-71310
- GHSA-xhf4-832v-7xcr
- GO-2026-6199

## Timeline

- 2026-07-31: disclosed
- 2026-07-31: patched: Fixed in version 1.75.0
- 2026-08-05: advisory

## References

- [https://api.github.com/users/cyberlanc3r](https://api.github.com/users/cyberlanc3r)
- [https://github.com/cyberlanc3r](https://github.com/cyberlanc3r)
- [https://api.github.com/users/cyberlanc3r/gists%7B/gist_id%7D](https://api.github.com/users/cyberlanc3r/gists%7B/gist_id%7D)
- [https://api.github.com/users/cyberlanc3r/repos](https://api.github.com/users/cyberlanc3r/repos)
- [https://avatars.githubusercontent.com/u/216992819?v=4](https://avatars.githubusercontent.com/u/216992819?v=4)
- [https://api.github.com/users/cyberlanc3r/events%7B/privacy%7D](https://api.github.com/users/cyberlanc3r/events%7B/privacy%7D)

## Related threats

- [Rclone B2 backend credential exposure on HTTP redirects](https://junglewise.ai/threats/cve-2026-116196-rclone-before-v1-75-2-contains-a-credential-exposure)
- [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)