RHSA-2026:55855: Important: libssh security update

libssh is a library which implements the SSH protocol. It can be used to implement client and server applications.Security Fix(es): libssh: libssh: information disclosure via short GSSAPI Curve25519 public key (CVE-2026-59842) libssh: libssh: denial of service via zero advertised channel packet size (CVE-2026-59843) libssh: libssh: denial of service via oversized SFTP read length (CVE-2026-59844) libssh: libssh: denial of service via unchecked ProxyCommand fork() failure (CVE-2026-59845) libssh: libssh: information disclosure via ProxyCommand %r username expansion (CVE-2026-59846) libssh: libssh: integrity downgrade via OpenSSL AES-GCM tag verification (CVE-2026-59847) libssh: libssh: denial of service via SFTP responses with unknown request IDs (CVE-2026-59848) libssh: libssh: denial of service via automatic certificate authentication loop (CVE-2026-59849) libssh: libssh: use-after-free via data callbacks on closed channels (CVE-2026-59850) libssh: libssh: authentication bypass via missing GSSAPI principal check (CVE-2026-59851) libssh: libssh: stack buffer overflow in SFTP server longname construction (CVE-2026-15370) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

— Red Hat