ALSA-2026:47755 (CVE-2026-55653)

Vulnerability from osv_almalinux – Published: 2026-07-29 00:00 – Updated: 2026-07-30 13:16 – Source website
VLAI
Summary
Moderate: openssh security update
Details

OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server.

Security Fix(es):

  • openssh: Local MITM of X11 forwarding via abstract UNIX socket pre-binding in AlmaLinux OpenSSH client versions (CVE-2026-55655)
  • openssh: Double free in AlmaLinux versions of OpenSSH DH-GEX client path during FIPS known-group validation leads to client-side denial of service (CVE-2026-55653)

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.

References
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "openssh"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "8.0p1-30.el8_10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "openssh-askpass"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "8.0p1-30.el8_10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "openssh-cavs"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "8.0p1-30.el8_10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "openssh-clients"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "8.0p1-30.el8_10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "openssh-keycat"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "8.0p1-30.el8_10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "openssh-ldap"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "8.0p1-30.el8_10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "openssh-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "8.0p1-30.el8_10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "pam_ssh_agent_auth"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.10.3-7.30.el8_10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server.  \n\nSecurity Fix(es):  \n\n  * openssh: Local MITM of X11 forwarding via abstract UNIX socket pre-binding in AlmaLinux OpenSSH client versions (CVE-2026-55655)\n  * openssh: Double free in AlmaLinux versions of OpenSSH DH-GEX client path during FIPS known-group validation leads to client-side denial of service (CVE-2026-55653)\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-2026:47755",
  "modified": "2026-07-30T13:16:14Z",
  "published": "2026-07-29T00:00:00Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:47755"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-55653"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-55655"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2462250"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2462351"
    },
    {
      "type": "ADVISORY",
      "url": "https://errata.almalinux.org/8/ALSA-2026-47755.html"
    }
  ],
  "related": [
    "CVE-2026-55653",
    "CVE-2026-55655"
  ],
  "schema_version": "1.7.0",
  "summary": "Moderate: openssh security update",
  "upstream": [
    "CVE-2026-55653",
    "CVE-2026-55655"
  ]
}



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