ubuntu-cve-2026-42257
Vulnerability from osv_ubuntu
Published
2026-05-09 20:16
Modified
2026-07-06 14:11
Summary
Details

Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.4.24, 0.5.14, and 0.6.4, several Net::IMAP commands accept a raw string argument that is sent to the server without validation or escaping. If this string is derived from user-controlled input, it may contain contain CRLF sequences, which an attacker can use to inject arbitrary IMAP commands. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.

Severity
5.8 (Medium)
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
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "jruby",
            "binary_version": "1.5.6-9+deb8u2build0.14.04.1~esm2"
          }
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      },
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        "name": "jruby",
        "purl": "pkg:deb/ubuntu/jruby@1.5.6-9+deb8u2build0.14.04.1~esm2?arch=source\u0026distro=esm-infra-legacy/trusty"
      },
      "ranges": [
        {
          "events": [
            {
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            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
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        "1.5.6-6",
        "1.5.6-7",
        "1.5.6-9+deb8u2build0.14.04.1~esm2"
      ]
    },
    {
      "ecosystem_specific": {
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        "binaries": [
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            "binary_name": "libruby2.3",
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          {
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          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "ruby2.3",
        "purl": "pkg:deb/ubuntu/ruby2.3@2.3.1-2~ubuntu16.04.16+esm14?arch=source\u0026distro=esm-infra-legacy/xenial"
      },
      "ranges": [
        {
          "events": [
            {
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            {
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          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
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        "2.3.0-2",
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        "2.3.1-2~16.04.6",
        "2.3.1-2~16.04.7",
        "2.3.1-2~16.04.9",
        "2.3.1-2~16.04.10",
        "2.3.1-2~16.04.11",
        "2.3.1-2~16.04.12",
        "2.3.1-2~ubuntu16.04.13",
        "2.3.1-2~ubuntu16.04.14",
        "2.3.1-2~ubuntu16.04.15",
        "2.3.1-2~ubuntu16.04.16",
        "2.3.1-2~ubuntu16.04.16+esm1",
        "2.3.1-2~ubuntu16.04.16+esm2",
        "2.3.1-2~ubuntu16.04.16+esm3",
        "2.3.1-2~ubuntu16.04.16+esm4",
        "2.3.1-2~ubuntu16.04.16+esm5",
        "2.3.1-2~ubuntu16.04.16+esm6",
        "2.3.1-2~ubuntu16.04.16+esm7",
        "2.3.1-2~ubuntu16.04.16+esm8",
        "2.3.1-2~ubuntu16.04.16+esm9",
        "2.3.1-2~ubuntu16.04.16+esm10",
        "2.3.1-2~ubuntu16.04.16+esm11",
        "2.3.1-2~ubuntu16.04.16+esm12"
      ]
    },
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    },
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            "binary_name": "ruby2.5",
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        "ecosystem": "Ubuntu:Pro:18.04:LTS",
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        "purl": "pkg:deb/ubuntu/ruby2.5@2.5.1-1ubuntu1.16+esm8?arch=source\u0026distro=esm-infra/bionic"
      },
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        "2.5.1-1ubuntu1.2",
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        "2.5.1-1ubuntu1.5",
        "2.5.1-1ubuntu1.6",
        "2.5.1-1ubuntu1.7",
        "2.5.1-1ubuntu1.8",
        "2.5.1-1ubuntu1.9",
        "2.5.1-1ubuntu1.10",
        "2.5.1-1ubuntu1.11",
        "2.5.1-1ubuntu1.12",
        "2.5.1-1ubuntu1.13",
        "2.5.1-1ubuntu1.14",
        "2.5.1-1ubuntu1.15",
        "2.5.1-1ubuntu1.16",
        "2.5.1-1ubuntu1.16+esm1",
        "2.5.1-1ubuntu1.16+esm3",
        "2.5.1-1ubuntu1.16+esm4",
        "2.5.1-1ubuntu1.16+esm5",
        "2.5.1-1ubuntu1.16+esm6",
        "2.5.1-1ubuntu1.16+esm7"
      ]
    },
    {
      "ecosystem_specific": {
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          {
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      "package": {
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        "name": "jruby",
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      },
      "ranges": [
        {
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            {
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            }
          ],
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        }
      ],
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        "9.1.17.0-1~18.04"
      ]
    },
    {
      "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"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
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            "binary_name": "jruby",
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      "package": {
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        "9.1.17.0-3",
        "9.1.17.0-3build5",
        "9.1.17.0-3build6"
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    },
    {
      "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",
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          "type": "ECOSYSTEM"
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      ],
      "versions": [
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        "3.0.2-7",
        "3.0.2-7ubuntu2",
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        "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"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "jruby",
            "binary_version": "9.4.6.0+ds-1ubuntu3"
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        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "jruby",
        "purl": "pkg:deb/ubuntu/jruby@9.4.6.0+ds-1ubuntu3?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
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          "type": "ECOSYSTEM"
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      "versions": [
        "9.3.9.0+ds-1",
        "9.4.5.0+ds-1",
        "9.4.5.0+ds-1ubuntu1",
        "9.4.6.0+ds-1ubuntu3"
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    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libruby3.2",
            "binary_version": "3.2.3-1ubuntu0.24.04.8"
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            "binary_name": "ruby3.2",
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      "package": {
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      ],
      "versions": [
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        "3.2.3-1build3",
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        "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"
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    },
    {
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    },
    {
      "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": [
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      ],
      "versions": [
        "3.3.8-2ubuntu2",
        "3.3.8-2ubuntu3"
      ]
    }
  ],
  "aliases": [],
  "details": "Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.4.24, 0.5.14, and 0.6.4, several Net::IMAP commands accept a raw string argument that is sent to the server without validation or escaping. If this string is derived from user-controlled input, it may contain contain CRLF sequences, which an attacker can use to inject arbitrary IMAP commands. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.",
  "id": "UBUNTU-CVE-2026-42257",
  "modified": "2026-07-06T14:11:22Z",
  "published": "2026-05-09T20:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-42257"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-42257"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/ruby/net-imap/releases/tag/v0.4.24"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/ruby/net-imap/releases/tag/v0.5.14"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/ruby/net-imap/releases/tag/v0.6.4"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/ruby/net-imap/security/advisories/GHSA-hm49-wcqc-g2xg"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8431-1"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8478-1"
    }
  ],
  "related": [
    "USN-8431-1",
    "USN-8478-1"
  ],
  "schema_version": "1.7.0",
  "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"
    }
  ],
  "upstream": [
    "CVE-2026-42257"
  ]
}



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Detection rules are retrieved from Rulezet.