When a user invokes curl using a schemeless URL combined with `--proto-default` sftp (or scp), a disconnect occurs between the tool layer and libcurl. The tool layer incorrectly infers the URL scheme, which erroneously bypasses the initialization of critical SSH security options like CURLOPT_SSH_HOST_PUBLIC_KEY_SHA256 and CURLOPT_SSH_KNOWNHOSTS. Conversely, the libcurl runtime successfully honors CURLOPT_DEFAULT_PROTOCOL and establishes the connection via SFTP/SCP as specified. Because the tool layer skipped the security configuration, these SSH host verification options are silently omitted, causing curl to connect to an unverified SSH remote host without throwing an error.
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alpine Linux | — | Upgrade curl | Jul 6, 2026 | Jul 3, 2026 |
| Amazon_linux_2023 | — | Upgrade libcurl-develUpgrade curl-debugsourceUpgrade libcurl-debuginfoUpgrade curlUpgrade curl-debuginfoUpgrade libcurlUpgrade libcurl-minimalUpgrade libcurl-minimal-debuginfoUpgrade curl-minimal-debuginfoUpgrade curl-minimal | Sep 30, 2026 | Jul 3, 2026 |
| Redhat_linux | — | Upgrade curl-debugsourceUpgrade curl-debuginfoUpgrade curlUpgrade libcurl-develUpgrade libcurlUpgrade libcurl-debuginfoUpgrade libcurl-minimal-debuginfoUpgrade libcurl-minimal | Jul 17, 2026 | Jul 3, 2026 |
| Ubuntu | — | Upgrade libcurl4-openssl-devUpgrade libcurl4-gnutls-devUpgrade libcurl4t64Upgrade libcurl3t64-gnutlsUpgrade curl | Jul 12, 2026 | Jul 9, 2026 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Aug 10, 2026 | Jul 3, 2026 |
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