Vulnerabilidad · Publicado 03/07/2026 · Actualizado 01/08/2026
When a libcurl-based application performs transfers via `SCP://` or `SFTP://`
and utilizes the `CURLOPT_SSH_KEYFUNCTION` callback, it may silently accept an
untrusted server. This vulnerability occurs when a server presents a host key
type that does not match the specific key type already recorded for that host
in the `known_hosts` file. Instead of rejecting the mismatch, the callback
mechanism fa…
When a libcurl-based application performs transfers via `SCP://` or `SFTP://` and utilizes the `CURLOPT_SSH_KEYFUNCTION` callback, it may silently accept an untrusted server. This vulnerability occurs when a server presents a host key type that does not match the specific key type already recorded for that host in the `known_hosts` file. Instead of rejecting the mismatch, the callback mechanism fails to properly enforce the restriction, allowing the connection to succeed without warning and risking a potential man-in-the-middle attack.
Score: 7.4/10 — Severidad: HIGH — Estado NIST: Analyzed
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Curl — Haxx
Publicado en NIST NVD.