CVE-2026-86411
curl curl
- curl curl
- Critical
- CVSS 9.1
- EPSS 0.15%
- No fixed version listed
Summary
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.
From the CVE record.
Read the original description
CVE record
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.
What to do
No fixed version listed
Affected products
| Product | Affected | Fixed in |
|---|---|---|
| curl curl | from 8.21.0 through 8.21.0 | None listed |
Advisories and fixes
- Public exploit hackerone.com
Scores and signals
- Exploitation
- No known exploitation
- Severity
- Critical, CVSS 9.1 (v3.1, scored by CISA-ADP)
- EPSS
- 0.15% chance of exploitation in the next 30 days (EPSS from FIRST, as of Oct 29, 2026)
- CISA's SSVC decision points
- Exploitation: proof of concept. Automatable: no. Technical impact: total. As of Oct 29, 2026.
- Weakness
- CWE-488: Exposure of Data Element to Wrong Session
- Vendor
- curl, curl
Timeline
- First listed as critical by cve.now. Affected and fixed versions come from the CVE record, once one is published.