CVE-2026-86411
FTP connection reuse inherits client-certificate
Reported by curl · Published October 20, 2026
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.
Fixed versions
Upgrade to a fixed version or later. Language registries are listed first, then Linux distributions, then vendor products.
| Package | Ecosystem | Fixed in |
|---|---|---|
| curl | Alpine | 8.23.0-r0 |
| curl | curl | 8.21.0 |
Risk scores
Affected products
| Vendor | Product | Versions |
|---|---|---|
| curl | curl | 8.21.0 |
| alpine | curl | 0 |
| curl | curl | 8.21.0 |
Timeline
- Oct 14, 2026 PoC Published (2 in total, the first dated here)
- Oct 20, 2026 CVE Published
- Oct 21, 2026 EPSS Score (5 in total, the first dated here)
Query this with the API
The same record, from the CLI:
vulnetix vdb vuln CVE-2026-86411
vulnetix vdb fixes CVE-2026-86411Or with curl, using the org id and key from your account page:
curl -s -H "Authorization: ApiKey ${VULNETIX_ORG_ID}:${VULNETIX_API_KEY}" \
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