A vulnerability exists where a new transfer that uses STARTTLS to upgrade the connection might reuse an existing live connection even though the TLS configuration mismatches so it should not.

wrong STARTTLS connection reuse

A vulnerability exists where a new transfer that uses STARTTLS to upgr ...

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.

Important: curl security, bug fix, and enhancement update

A vulnerability exists where a new transfer that uses STARTTLS to upgrade the connection might reuse an existing live connection even though the TLS configuration mismatches so it should not.

ELSA-2026-57462: curl security, bug fix, and enhancement update (IMPORTANT)