Vulnerability details
CVE-2026-86411
curl curl
FTP connection reuse inherits client-certificate
CVSS 3.1
9.1Critical
Official 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.
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 9.1Critical | 3.1 | CISA ADP / Vulnrichment (CISA-ADP) | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| curl | curl | 8.21.0 ≤ v ≤ 8.21.0 | CVEProject cvelistV5 (CNA) |
References and advisories
3
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Details
- Published
- 2026-10-20
- Last updated
- 2026-10-29
- State
- Published
- Assigner (CNA)
- curl
- Kolun priority
- 23 · Low
Exploit prediction (EPSS)
0.43%
Probability of exploitation in 30 days
37.8%
Percentile (among all CVEs)
SSVC assessment (CISA)
- Automatable
- No
- Exploitation
- Proof of concept
- Technical impact
- Total
Weaknesses (CWE)
- CWE-488Exposure of Data Element to Wrong Session