{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:ruby-lang:net\\:\\:imap:*:*:*:*:*:ruby:*:*",
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "0.3.10"
              },
              {
                "introduced": "0.4.0"
              },
              {
                "fixed": "0.4.24"
              },
              {
                "introduced": "0.5.0"
              },
              {
                "fixed": "0.5.14"
              },
              {
                "introduced": "0.6.0"
              },
              {
                "fixed": "0.6.4"
              }
            ],
            "source": [
              "CPE_RANGE",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "ec89812d3c986d6394d3bc0b93048e704aec6af9"
            },
            {
              "introduced": "a9459de2c725563d27943e73a92a61f69ef9b048"
            },
            {
              "fixed": "24a4e770b43230286a05aa2a9746cdbb3eb8485e"
            },
            {
              "introduced": "cc13c91c65b78ee33ebf4960d547173e761cafdc"
            },
            {
              "fixed": "4063bc1d1d3e21046544ed7a2c131e5f886bab01"
            },
            {
              "introduced": "567518cae5500f7c4776a1fd4e9bbd599e98b9bf"
            },
            {
              "fixed": "3e490673dca65d0cfeeeb3fbf1fdaa188d6f27c4"
            },
            {
              "fixed": "0ede4c40b1523dfeaf95777b2678e54cc0fd9618"
            },
            {
              "fixed": "97e2488fb5401a1783bddd959dde007d9fbce42c"
            },
            {
              "fixed": "f79d35bf5833f186e81044c57c843eda30c873da"
            }
          ],
          "repo": "https://github.com/ruby/net-imap",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-vcgp-9326-pqcp"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-392",
      "CWE-393",
      "CWE-636",
      "CWE-754",
      "CWE-841"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42246.json"
  },
  "details": "Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.3.10, 0.4.24, 0.5.14, and 0.6.4, a man-in-the-middle attacker can cause Net::IMAP#starttls to return \"successfully\", without starting TLS. This issue has been patched in versions 0.3.10, 0.4.24, 0.5.14, and 0.6.4.",
  "id": "CVE-2026-42246",
  "modified": "2026-07-11T03:53:54.619339269Z",
  "published": "2026-05-09T19:33:17.880Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/ruby/net-imap/releases/tag/v0.3.10"
    },
    {
      "type": "WEB",
      "url": "https://github.com/ruby/net-imap/releases/tag/v0.4.24"
    },
    {
      "type": "WEB",
      "url": "https://github.com/ruby/net-imap/releases/tag/v0.5.14"
    },
    {
      "type": "WEB",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42246.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:33462"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:33512"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:33514"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:33515"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:33540"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:33551"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:33552"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:33565"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:33576"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:33577"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:33630"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:33721"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:34076"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:35834"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:35866"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:35867"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:35895"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:36099"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:37238"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:37397"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/security/cve/CVE-2026-42246"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42246.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/ruby/net-imap/security/advisories/GHSA-vcgp-9326-pqcp"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42246"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2468499"
    },
    {
      "type": "FIX",
      "url": "https://github.com/ruby/net-imap/commit/0ede4c40b1523dfeaf95777b2678e54cc0fd9618"
    },
    {
      "type": "FIX",
      "url": "https://github.com/ruby/net-imap/commit/24a4e770b43230286a05aa2a9746cdbb3eb8485e"
    },
    {
      "type": "FIX",
      "url": "https://github.com/ruby/net-imap/commit/97e2488fb5401a1783bddd959dde007d9fbce42c"
    },
    {
      "type": "FIX",
      "url": "https://github.com/ruby/net-imap/commit/f79d35bf5833f186e81044c57c843eda30c873da"
    }
  ],
  "schema_version": "1.7.5",
  "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"
    }
  ],
  "summary": "net-imap vulnerable to STARTTLS stripping via invalid response timing"
}