{"id":"RLSA-2026:55855","summary":"Important: libssh security update","details":"libssh is a library which implements the SSH protocol. It can be used to implement client and server applications.\n\nSecurity Fix(es):\n\n* libssh: libssh: information disclosure via short GSSAPI Curve25519 public key (CVE-2026-59842)\n\n* libssh: libssh: denial of service via zero advertised channel packet size (CVE-2026-59843)\n\n* libssh: libssh: denial of service via oversized SFTP read length (CVE-2026-59844)\n\n* libssh: libssh: denial of service via unchecked ProxyCommand fork() failure (CVE-2026-59845)\n\n* libssh: libssh: information disclosure via ProxyCommand %r username expansion (CVE-2026-59846)\n\n* libssh: libssh: integrity downgrade via OpenSSL AES-GCM tag verification (CVE-2026-59847)\n\n* libssh: libssh: denial of service via SFTP responses with unknown request IDs (CVE-2026-59848)\n\n* libssh: libssh: denial of service via automatic certificate authentication loop (CVE-2026-59849)\n\n* libssh: libssh: use-after-free via data callbacks on closed channels (CVE-2026-59850)\n\n* libssh: libssh: authentication bypass via missing GSSAPI principal check (CVE-2026-59851)\n\n* libssh: libssh: stack buffer overflow in SFTP server longname construction (CVE-2026-15370)\n\nFor 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.","modified":"2026-08-18T12:30:03.262239025Z","published":"2026-08-18T12:07:31.722662Z","upstream":["CVE-2026-15370","CVE-2026-59842","CVE-2026-59843","CVE-2026-59844","CVE-2026-59845","CVE-2026-59846","CVE-2026-59847","CVE-2026-59848","CVE-2026-59849","CVE-2026-59850","CVE-2026-59851"],"database_specific":{"source_advisory":"RHSA-2026:55855","license":"CC-BY-4.0","license_url":"https://creativecommons.org/licenses/by/4.0/"},"references":[{"type":"ADVISORY","url":"https://errata.rockylinux.org/RLSA-2026:55855"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2498180"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2498183"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2498168"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2498184"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2498181"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2498178"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2498176"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2499049"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2498177"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2498182"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2498179"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:55855"}],"affected":[{"package":{"name":"libssh","ecosystem":"Rocky Linux:10","purl":"pkg:rpm/rocky-linux/libssh?distro=rocky-linux-10&epoch=0"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0:0.12.0-3.el10_2"}],"database_specific":{"yum_repository":"BaseOS"}}],"database_specific":{"source":"https://storage.googleapis.com/resf-osv-data/RLSA-2026:55855.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}],"credits":[{"name":"Rocky Enterprise Software Foundation"},{"name":"Red Hat"}]}