FTP connection reuse inherits client-certificate

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-86411
StatePUBLISHED
Assignercurl
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-20 20:17:25 UTC
Updated2026-10-20 20:17:25 UTC
DescriptionAn `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.

Risk And Classification

Problem Types: CWE-488 Exposure of Data Element to Wrong Session

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Curl Curl affected 8.21.0 8.21.0 semver Not specified

References

ReferenceSourceLinkTags
hackerone.com/reports/3973190 2499f714-1537-4658-8207-48ae4bb9eae9 hackerone.com
curl.se/docs/CVE-2026-86411.html 2499f714-1537-4658-8207-48ae4bb9eae9 curl.se
curl.se/docs/CVE-2026-86411.json 2499f714-1537-4658-8207-48ae4bb9eae9 curl.se
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Stanislav Fort (Aisle Research) (en)

CNA: Stefan Eissing (en)

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