CVE-2026-12064
proto-default skips SSH verification
Description
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.
INFO
Published Date :
July 3, 2026, 6:13 a.m.
Last Modified :
July 3, 2026, 6:13 a.m.
Remotely Exploit :
No
Source :
curl
Affected Products
The following products are affected by CVE-2026-12064
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
Solution
- Update curl to a version that corrects protocol handling.
- Configure explicit SSH host verification options.
- Verify SSH host keys before establishing connections.
- Avoid using schemeless URLs with --proto-default.
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CVE-2026-12064 vulnerability anywhere in the article.