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usn-8478-1
Vulnerability from osv_ubuntu
Published
2025-06-29 09:15
Modified
2026-06-30 15:55
Summary
ruby2.7, ruby3.0, ruby3.2, ruby3.3 vulnerabilities
Details

It was discovered that Ruby's Net::IMAP library did not properly verify that TLS encryption was started after issuing a STARTTLS command. A remote attacker could use this to perform a machine-in-the-middle attack and silently bypass TLS encryption. (CVE-2026-42246)

It was discovered that Ruby's Net::IMAP library did not validate string arguments passed to certain commands. A remote attacker could use this to inject arbitrary IMAP commands. (CVE-2026-42257)

It was discovered that Ruby's Net::IMAP library was vulnerable to a denial of service attack when authenticating with SCRAM-SHA1 or SCRAM-SHA256. A hostile server could send a very large iteration count value to cause excessive computation in the client. This issue only affected ruby3.3. (CVE-2026-42256)

References
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2026-42246",
              "severity": [
                {
                  "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N",
                  "type": "CVSS_V4"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-42257",
              "severity": [
                {
                  "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N",
                  "type": "CVSS_V4"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:Pro:20.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "libruby2.7",
            "binary_version": "2.7.0-5ubuntu1.18+esm5"
          },
          {
            "binary_name": "ruby2.7",
            "binary_version": "2.7.0-5ubuntu1.18+esm5"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "ruby2.7",
        "purl": "pkg:deb/ubuntu/ruby2.7@2.7.0-5ubuntu1.18+esm5?arch=source\u0026distro=esm-infra/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.7.0-5ubuntu1.18+esm5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.7.0-1",
        "2.7.0-2",
        "2.7.0-3",
        "2.7.0-4",
        "2.7.0-4ubuntu1",
        "2.7.0-5ubuntu1",
        "2.7.0-5ubuntu1.1",
        "2.7.0-5ubuntu1.2",
        "2.7.0-5ubuntu1.3",
        "2.7.0-5ubuntu1.4",
        "2.7.0-5ubuntu1.5",
        "2.7.0-5ubuntu1.6",
        "2.7.0-5ubuntu1.7",
        "2.7.0-5ubuntu1.8",
        "2.7.0-5ubuntu1.9",
        "2.7.0-5ubuntu1.10",
        "2.7.0-5ubuntu1.11",
        "2.7.0-5ubuntu1.12",
        "2.7.0-5ubuntu1.13",
        "2.7.0-5ubuntu1.14",
        "2.7.0-5ubuntu1.15",
        "2.7.0-5ubuntu1.16",
        "2.7.0-5ubuntu1.17",
        "2.7.0-5ubuntu1.18",
        "2.7.0-5ubuntu1.18+esm1",
        "2.7.0-5ubuntu1.18+esm3",
        "2.7.0-5ubuntu1.18+esm4"
      ]
    },
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2026-42246",
              "severity": [
                {
                  "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N",
                  "type": "CVSS_V4"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-42257",
              "severity": [
                {
                  "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N",
                  "type": "CVSS_V4"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:22.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libruby3.0",
            "binary_version": "3.0.2-7ubuntu2.13"
          },
          {
            "binary_name": "ruby3.0",
            "binary_version": "3.0.2-7ubuntu2.13"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "ruby3.0",
        "purl": "pkg:deb/ubuntu/ruby3.0@3.0.2-7ubuntu2.13?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.0.2-7ubuntu2.13"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.0.2-5ubuntu1",
        "3.0.2-7",
        "3.0.2-7ubuntu2",
        "3.0.2-7ubuntu2.1",
        "3.0.2-7ubuntu2.2",
        "3.0.2-7ubuntu2.3",
        "3.0.2-7ubuntu2.4",
        "3.0.2-7ubuntu2.5",
        "3.0.2-7ubuntu2.6",
        "3.0.2-7ubuntu2.7",
        "3.0.2-7ubuntu2.8",
        "3.0.2-7ubuntu2.10",
        "3.0.2-7ubuntu2.11",
        "3.0.2-7ubuntu2.12"
      ]
    },
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2026-42246",
              "severity": [
                {
                  "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N",
                  "type": "CVSS_V4"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-42257",
              "severity": [
                {
                  "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N",
                  "type": "CVSS_V4"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:24.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libruby3.2",
            "binary_version": "3.2.3-1ubuntu0.24.04.8"
          },
          {
            "binary_name": "ruby3.2",
            "binary_version": "3.2.3-1ubuntu0.24.04.8"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "ruby3.2",
        "purl": "pkg:deb/ubuntu/ruby3.2@3.2.3-1ubuntu0.24.04.8?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.2.3-1ubuntu0.24.04.8"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.2.3-1",
        "3.2.3-1build2",
        "3.2.3-1build3",
        "3.2.3-1ubuntu0.24.04.1",
        "3.2.3-1ubuntu0.24.04.3",
        "3.2.3-1ubuntu0.24.04.5",
        "3.2.3-1ubuntu0.24.04.6",
        "3.2.3-1ubuntu0.24.04.7"
      ]
    },
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2026-42246",
              "severity": [
                {
                  "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N",
                  "type": "CVSS_V4"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-42256",
              "severity": [
                {
                  "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
                  "type": "CVSS_V4"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-42257",
              "severity": [
                {
                  "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N",
                  "type": "CVSS_V4"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:26.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libruby3.3",
            "binary_version": "3.3.8-2ubuntu3.1"
          },
          {
            "binary_name": "ruby3.3",
            "binary_version": "3.3.8-2ubuntu3.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "ruby3.3",
        "purl": "pkg:deb/ubuntu/ruby3.3@3.3.8-2ubuntu3.1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.3.8-2ubuntu3.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.3.8-2ubuntu2",
        "3.3.8-2ubuntu3"
      ]
    }
  ],
  "aliases": [],
  "details": "It was discovered that Ruby\u0027s Net::IMAP library did not properly verify\nthat TLS encryption was started after issuing a STARTTLS command. A remote\nattacker could use this to perform a machine-in-the-middle attack and silently\nbypass TLS encryption. (CVE-2026-42246)\n\nIt was discovered that Ruby\u0027s Net::IMAP library did not validate\nstring arguments passed to certain commands. A remote attacker could use\nthis to inject arbitrary IMAP commands. (CVE-2026-42257)\n\nIt was discovered that Ruby\u0027s Net::IMAP library was vulnerable to a\ndenial of service attack when authenticating with SCRAM-SHA1 or\nSCRAM-SHA256. A hostile server could send a very large iteration count\nvalue to cause excessive computation in the client. This issue only\naffected ruby3.3. (CVE-2026-42256)",
  "id": "USN-8478-1",
  "modified": "2026-06-30T15:55:21Z",
  "published": "2025-06-29T09:15:31Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8478-1"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-42246"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-42256"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-42257"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "summary": "ruby2.7, ruby3.0, ruby3.2, ruby3.3 vulnerabilities",
  "upstream": [
    "UBUNTU-CVE-2026-42246",
    "UBUNTU-CVE-2026-42256",
    "UBUNTU-CVE-2026-42257"
  ]
}



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