{"id":"ALSA-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  * libssh: libssh: denial of service via zero advertised channel packet size (CVE-2026-59843)\n  * libssh: libssh: denial of service via oversized SFTP read length (CVE-2026-59844)\n  * libssh: libssh: denial of service via unchecked ProxyCommand fork() failure (CVE-2026-59845)\n  * libssh: libssh: information disclosure via ProxyCommand %r username expansion (CVE-2026-59846)\n  * libssh: libssh: integrity downgrade via OpenSSL AES-GCM tag verification (CVE-2026-59847)\n  * libssh: libssh: denial of service via SFTP responses with unknown request IDs (CVE-2026-59848)\n  * libssh: libssh: denial of service via automatic certificate authentication loop (CVE-2026-59849)\n  * libssh: libssh: use-after-free via data callbacks on closed channels (CVE-2026-59850)\n  * libssh: libssh: authentication bypass via missing GSSAPI principal check (CVE-2026-59851)\n  * libssh: libssh: stack buffer overflow in SFTP server longname construction (CVE-2026-15370)\n\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.\n","modified":"2026-08-18T12:26:53.859696632Z","published":"2026-08-17T00:00:00Z","related":["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"],"references":[{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:55855"},{"type":"REPORT","url":"https://access.redhat.com/security/cve/CVE-2026-15370"},{"type":"REPORT","url":"https://access.redhat.com/security/cve/CVE-2026-59842"},{"type":"REPORT","url":"https://access.redhat.com/security/cve/CVE-2026-59843"},{"type":"REPORT","url":"https://access.redhat.com/security/cve/CVE-2026-59844"},{"type":"REPORT","url":"https://access.redhat.com/security/cve/CVE-2026-59845"},{"type":"REPORT","url":"https://access.redhat.com/security/cve/CVE-2026-59846"},{"type":"REPORT","url":"https://access.redhat.com/security/cve/CVE-2026-59847"},{"type":"REPORT","url":"https://access.redhat.com/security/cve/CVE-2026-59848"},{"type":"REPORT","url":"https://access.redhat.com/security/cve/CVE-2026-59849"},{"type":"REPORT","url":"https://access.redhat.com/security/cve/CVE-2026-59850"},{"type":"REPORT","url":"https://access.redhat.com/security/cve/CVE-2026-59851"},{"type":"REPORT","url":"https://bugzilla.redhat.com/2498168"},{"type":"REPORT","url":"https://bugzilla.redhat.com/2498176"},{"type":"REPORT","url":"https://bugzilla.redhat.com/2498177"},{"type":"REPORT","url":"https://bugzilla.redhat.com/2498178"},{"type":"REPORT","url":"https://bugzilla.redhat.com/2498179"},{"type":"REPORT","url":"https://bugzilla.redhat.com/2498180"},{"type":"REPORT","url":"https://bugzilla.redhat.com/2498181"},{"type":"REPORT","url":"https://bugzilla.redhat.com/2498182"},{"type":"REPORT","url":"https://bugzilla.redhat.com/2498183"},{"type":"REPORT","url":"https://bugzilla.redhat.com/2498184"},{"type":"REPORT","url":"https://bugzilla.redhat.com/2499049"},{"type":"ADVISORY","url":"https://errata.almalinux.org/10/ALSA-2026-55855.html"}],"affected":[{"package":{"name":"libssh","ecosystem":"AlmaLinux:10","purl":"pkg:rpm/almalinux/libssh"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.12.0-3.el10_2"}]}],"database_specific":{"source":"https://github.com/AlmaLinux/osv-database/blob/master/advisories/almalinux10/ALSA-2026:55855.json"}},{"package":{"name":"libssh-config","ecosystem":"AlmaLinux:10","purl":"pkg:rpm/almalinux/libssh-config"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.12.0-3.el10_2"}]}],"database_specific":{"source":"https://github.com/AlmaLinux/osv-database/blob/master/advisories/almalinux10/ALSA-2026:55855.json"}},{"package":{"name":"libssh-devel","ecosystem":"AlmaLinux:10","purl":"pkg:rpm/almalinux/libssh-devel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.12.0-3.el10_2"}]}],"database_specific":{"source":"https://github.com/AlmaLinux/osv-database/blob/master/advisories/almalinux10/ALSA-2026:55855.json"}}],"schema_version":"1.9.0"}