rlsa-2026:55855
Vulnerability from osv_rocky
Published
2026-08-18 12:07
Modified
2026-08-23 18:09
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.

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.

Severity
8.8 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Credits
Rocky Enterprise Software Foundation
Red Hat
References
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "Rocky Linux:10",
        "name": "libssh",
        "purl": "pkg:rpm/rocky-linux/libssh?distro=rocky-linux-10\u0026epoch=0"
      },
      "ranges": [
        {
          "database_specific": {
            "yum_repository": "BaseOS"
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0:0.12.0-3.el10_2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "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"
  },
  "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.",
  "id": "RLSA-2026:55855",
  "modified": "2026-08-23T18:09:39.654249Z",
  "published": "2026-08-18T12:07:31.722662Z",
  "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"
    }
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Important: libssh security update",
  "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"
  ]
}



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