CVE-2026-86411: critical vulnerability in curl
FTP connection reuse inherits client-certificate
Published · Updated
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28Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 9.1epss 0.4%
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:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Affected products
curl · curlRelated CVEs — curl
In the same product, most dangerous first.