# CVE-2025-10966: curl missing SFTP host verification in wolfSSH backend

Source: https://junglewise.ai/threats/cve-2025-10966-curl-missing-sftp-host-verification-in-wolfssh-backend  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2025-11-07. Updated: 2026-06-02  
License: CC BY 4.0 with a link back

CVE-2025-10966 · Severity: medium · CVSS 4.3 · Published 2025-11-07

curl is a widely used tool and library for transferring data over various network protocols. A security flaw was identified in how it handles secure file transfers (SFTP) when using a specific technical component called wolfSSH. This flaw prevents the software from verifying the identity of the remote server, which could allow an attacker to intercept or manipulate data during transmission without being detected.

Technologies: [Haxx Curl](https://junglewise.ai/threats/technologies/curl). Vendors: [Haxx](https://junglewise.ai/threats/vendors/haxx).

## Quick answers

**Is CVE-2025-10966 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2025-10966 being exploited in the wild.

**How severe is CVE-2025-10966?** Medium severity, with a CVSS score of 4.3, published 7 November 2025.

**Which products and versions are affected?** Haxx Curl 7.69.0 to 8.16.0.

**Is there a fix for CVE-2025-10966?** A patch was published on 2025-11-05: Fixed in curl version 8.17.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2025-10966 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2025-10966?** Check whether you run Haxx Curl 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.

## Technical details

A vulnerability exists in curl's wolfSSH backend where host verification mechanisms were omitted during the implementation of SFTP support. This flaw (CWE-322) means curl does not verify the remote host's identity against a known_hosts file, making it susceptible to man-in-the-middle (MITM) attacks. The issue specifically affects builds of curl configured to use wolfSSH as the SSH backend; other backends like libssh2 or libssh are not impacted. The vulnerability was addressed in curl 8.17.0 by completely removing support for the wolfSSH backend, which was considered incomplete and experimental.

## Affected products

- haxx curl 7.69.0 to 8.16.0

## Timeline

- 2025-09-23: disclosed: Reported to the curl project by Stanislav Fort.
- 2025-11-05: patched: Fixed in curl version 8.17.0.
- 2025-11-07: advisory: NVD publication date.

## References

- [https://curl.se/docs/CVE-2025-10966.html](https://curl.se/docs/CVE-2025-10966.html)
- [https://curl.se/docs/CVE-2025-10966.json](https://curl.se/docs/CVE-2025-10966.json)
- [https://hackerone.com/reports/3355218](https://hackerone.com/reports/3355218)
- [http://www.openwall.com/lists/oss-security/2025/11/05/2](http://www.openwall.com/lists/oss-security/2025/11/05/2)
- [https://cert-portal.siemens.com/productcert/html/ssa-253495.html](https://cert-portal.siemens.com/productcert/html/ssa-253495.html)

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