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CriticalFix available

ruby-net-imap — security advisory

Type: advisorySources: OSVAdvisory ID: ALPINE-CVE-2026-42257

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.

Products
ruby-net-imap
Affected versions
Not specified
Fixed versions
0.4.25-r0
CVEs
CVE-2026-42257
Confirmed fixed CVEs
Not specified
Updated in this feed
1 Nov 2026, 17:57 UTC · Revision 1

Source evidence

ALPINE-CVE-2026-42257

core-osv · Original source

Published 9 May 2026, 20:16 UTC

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.

osv:ALPINE-CVE-2026-42257

ruby-net-imap

Fixed versions: 0.4.25-r0

Complete source record
{
  "id": "cad6e33b375d6320e7ac267f189a75c5940623b3accf579556a3ce1df7ab2f9d",
  "url": "https://osv.dev/vulnerability/ALPINE-CVE-2026-42257",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ALPINE-CVE-2026-42257",
    "summary": "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.",
    "evidence": "osv:ALPINE-CVE-2026-42257",
    "products": [
      {
        "name": {
          "value": "ruby-net-imap",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "0.4.25-r0",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "critical",
    "structured": {
      "id": "ALPINE-CVE-2026-42257",
      "aliases": [
        "ALPINE-CVE-2026-42257"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "0.4.25-r0"
                }
              ]
            }
          ],
          "package": {
            "name": "ruby-net-imap",
            "purl": "pkg:apk/alpine/ruby-net-imap?arch=source",
            "ecosystem": "Alpine:v3.21"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2026-42257.json"
          },
          "ecosystem_specific": {}
        }
      ],
      "modified": "2026-10-27T12:30:04.141672615Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-42257"
      ],
      "references": [
        "https://security.alpinelinux.org/vuln/CVE-2026-42257"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-42257",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 461540,
  "published_at": "2026-05-09T20:16:28.463+00:00"
}