Critical Remote Code Execution Vulnerability in libssh2 Client Library Require Urgent Mitigation
A suite of severe vulnerabilities has been disclosed in libssh2 (an SSH client library widely embedded in software such as curl, Git GUI clients, PHP, backup tools, and many IoT/embedded devices). The most critical, CVE-2026-55200 (CVSS 9.2/9.8), is a memory corruption bug in libssh2’s ssh2_transport_read() triggered by a malicious SSH server pre-authentication via a crafted packet_length.