# CVE-2026-86411: FTP connection reuse inherits client-certificate

CVE-2026-86411 is fixed in curl on 1 platform, first by DEBIAN-CVE-2026-86411, released October 16, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-86411
- Priority: High
- CVSS: 9.1 (Low)
- EPSS: 0.0043
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 20, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-86411

## Description

An `ftp://` transfer configured with `CURLUSESSL_NONE` can reuse a pooled FTP control connection that a previous easy handle upgraded with `STARTTLS` and authenticated using a client certificate. The second handle performs neither a new TLS handshake nor a new FTP login, so the server continues to authorize it under the first handle's certificate identity.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | curl Debian 14 | 8.22.0-1 | [DEBIAN-CVE-2026-86411](https://patchblox.com/security/data/fix/linux/debian-cve-2026-86411.md) | Oct 16, 2026 |
| Linux | curl sles 15.6 | 8.22.0-150600.4.58.1 | [SUSE-SU-2026:5069-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-5069-1.md) | Nov 7, 2026 |
| Linux | curl sles 15.7 | 8.22.0-150700.7.33.1 | [SUSE-SU-2026:5068-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-5068-1.md) | Nov 7, 2026 |

---

Data as of 2026-11-09T13:31:49Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.