{"schema_version": "1.7.0", "id": "RLSA-2026:55855", "modified": "2026-08-18T12:10:03.244874Z", "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"], "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.", "severity": [{"type": "CVSS_V3", "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}], "affected": [{"package": {"ecosystem": "Rocky Linux:10", "name": "libssh", "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"}}]}], "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"}], "credits": [{"name": "Rocky Enterprise Software Foundation"}, {"name": "Red Hat"}], "database_specific": {"license": "CC-BY-4.0", "license_url": "https://creativecommons.org/licenses/by/4.0/", "source_advisory": "RHSA-2026:55855"}}