ALSA-2026:55855

Vulnerability from osv_almalinux – Published: 2026-08-17 00:00 – Updated: 2026-08-18 11:15 – Source website
VLAI
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.


{
  "affected": [
    {
      "package": {
        "ecosystem": "AlmaLinux:10",
        "name": "libssh"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.12.0-3.el10_2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:10",
        "name": "libssh-config"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.12.0-3.el10_2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:10",
        "name": "libssh-devel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.12.0-3.el10_2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "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",
  "id": "ALSA-2026:55855",
  "modified": "2026-08-18T11:15:41Z",
  "published": "2026-08-17T00:00:00Z",
  "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"
    }
  ],
  "related": [
    "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",
    "CVE-2026-15370"
  ],
  "summary": "Important: libssh security update"
}



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