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ubuntu-cve-2026-54548
Vulnerability from osv_ubuntu
Published
2026-08-26 15:16
Modified
2026-09-02 16:20
Summary
Details

kas is a setup tool for bitbake based projects. Prior to 5.4, internal SSH key setup triggered by SSH_PRIVATE_KEY or SSH_PRIVATE_KEY_FILE creates ~/.ssh/config when no user-specific SSH configuration exists and adds a global Host * rule containing StrictHostKeyChecking no. In kas/libcmds.py, ssh_no_host_key_check() runs without checking ctx.managed_env, so the setting persists after kas exits and affects future SSH sessions by the same local user, extending beyond the intended short-lived continuous integration environment. A later SSH connection can therefore accept an attacker-controlled host key without verification, increasing the risk of a man-in-the-middle attack that compromises session confidentiality or integrity. This issue is fixed in version 5.4.

Severity
3.3 (Low)
CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "kas",
            "binary_version": "2.6.3-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "kas",
        "purl": "pkg:deb/ubuntu/kas@2.6.3-2?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.3.3-2",
        "2.5-1",
        "2.6.3-2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "kas",
            "binary_version": "4.0-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "kas",
        "purl": "pkg:deb/ubuntu/kas@4.0-1?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.0-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "kas",
            "binary_version": "4.8.1-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "kas",
        "purl": "pkg:deb/ubuntu/kas@4.8.1-2?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.7-1",
        "4.8.1-1",
        "4.8.1-2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "kas",
            "binary_version": "5.1-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "kas",
        "purl": "pkg:deb/ubuntu/kas@5.1-1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.8.1-2",
        "5.0-1",
        "5.1-1"
      ]
    }
  ],
  "aliases": [],
  "details": "kas is a setup tool for bitbake based projects. Prior to 5.4, internal SSH key setup triggered by SSH_PRIVATE_KEY or SSH_PRIVATE_KEY_FILE creates ~/.ssh/config when no user-specific SSH configuration exists and adds a global Host * rule containing StrictHostKeyChecking no. In kas/libcmds.py, ssh_no_host_key_check() runs without checking ctx.managed_env, so the setting persists after kas exits and affects future SSH sessions by the same local user, extending beyond the intended short-lived continuous integration environment. A later SSH connection can therefore accept an attacker-controlled host key without verification, increasing the risk of a man-in-the-middle attack that compromises session confidentiality or integrity. This issue is fixed in version 5.4.",
  "id": "UBUNTU-CVE-2026-54548",
  "modified": "2026-09-02T16:20:00Z",
  "published": "2026-08-26T15:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-54548"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-54548"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/siemens/kas/security/advisories/GHSA-mv8m-v9v6-5f94"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-54548"
  ]
}



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