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.
References (3)
Core 3
Core References
Scores
CVSS v3
7.5
EPSS
0.0057
EPSS Percentile
43.4%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CISA SSVC
Vulnrichment
Exploitation
poc
Automatable
yes
Technical Impact
partial
Details
CWE
CWE-295
Status
published
Products (42)
curl/curl
7.81.0
curl/curl
7.82.0
curl/curl
7.83.0
curl/curl
7.83.1
curl/curl
7.84.0
curl/curl
7.85.0
curl/curl
7.86.0
curl/curl
7.87.0
curl/curl
7.88.0
curl/curl
7.88.1
... and 32 more
Published
Jul 03, 2026
Tracked Since
Jul 03, 2026