CVE-2026-12064
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk36th percentile - higher than 36% of all known CVEs
Summary
A vulnerability in curl causes the tool layer to skip initialization of critical SSH security options like CURLOPT_SSH_HOST_PUBLIC_KEY_SHA256 and CURLOPT_SSH_KNOWNHOSTS when using a schemeless URL with `--proto-default sftp` (or scp), while libcurl establishes the SFTP/SCP connection. This results in curl connecting to an unverified SSH remote host without error.
Risk Assessment
The organization is at risk of man-in-the-middle (MITM) attacks on SFTP/SCP connections, as the omission of SSH host key verification allows an attacker to impersonate the remote server undetected.
Recommendation
Immediately update curl to a patched version and avoid using schemeless URLs with `--proto-default sftp` until the fix is applied.
Other vulnerabilities in curl
See all- CVE-2022-27775High
An information disclosure vulnerability exists in curl versions 7.65.0 to 7.82.0 that allows reusing a connection using an IPv6 address with a different zone id.
- CVE-2022-22576High
An improper authentication vulnerability exists in curl versions 7.33.0 to 7.82.0 which might allow reuse of OAUTH2-authenticated connections without properly ensuring that the connection was authenticated with the same credentials. This affects SASL-enabled protocols: SMPTP(S), IMAP(S), POP3(S), and LDAP(S) (openldap only).
- CVE-2024-9681Medium
When curl is asked to use HSTS, the expiry time for a subdomain might overwrite a parent domain's cache entry, making it end sooner or later than otherwise intended. This affects applications using HSTS and URLs with the insecure HTTP:// scheme.
- CVE-2024-11053Low
When curl is asked to use a `.netrc` file for credentials and to follow HTTP redirects, it could leak the password used for the first host to the followed-to host under certain circumstances. This flaw only manifests if the netrc file has an entry matching the redirect target hostname.
- CVE-2024-8096Medium
When curl is told to use the Certificate Status Request TLS extension (OCSP stapling) to verify the server certificate, it might fail to detect some OCSP problems and wrongly consider the response as fine if the returned status reports another error than expected.
- CVE-2026-8926Critical
A vulnerability in curl causes it to incorrectly use another user's password from the .netrc file when a URL with a username (without password) is provided, potentially leading to credential confusion.
- CVE-2026-8925Critical
A double-free vulnerability has been found in the curl library's SASL authentication handling. The GSASL context is cleaned up twice without clearing the pointer, causing free() to be called on the same memory region twice.
- CVE-2026-8924Critical
A flaw in curl's cookie parsing logic allows a malicious HTTP server to set 'super cookies' that bypass the Public Suffix List check. This enables an attacker-controlled origin to inject cookies that curl subsequently scopes and transmits to unrelated third-party domains.
- CVE-2023-38545Critical
CVE-2023-38545 is a vulnerability related to heap buffer overflow during the SOCKS5 proxy handshake in curl. The issue arises when curl passes a hostname that is too long to the proxy, leading to incorrect data copying.
- CVE-2026-11586High
Curl lacks an upper bound on memory allocation for unacknowledged WebSocket PING frames, allowing a malicious server to exhaust all available memory by sending rapid sequential PING messages.
Original NVD description (English source)
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.