ruby-advisory-db/gems/net-imap/CVE-2026-47242.yml at master · rubysec/ruby-advisory-db · GitHub

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---
gem: net-imap
cve: 2026-47242
ghsa: 46q3-7gv7-qmgg
url: https://www.cve.org/CVERecord?id=CVE-2026-47242
title: 'Net::IMAP: Command Injection via ID command argument'
date: 2026-06-09
description: |
  ### Summary

  Two `Net::IMAP` commands, `#id` and `#enable`, do not validate their
  arguments.  Arguments to either command could be used by an attacker
  to inject arbitrary IMAP commands.

  Please note that passing untrusted inputs to these commands is usually
  inappropriate and expected to be uncommon.

  ### Details

  When `Net::IMAP#id` is called with a hash argument, although the ID
  field value strings are correctly quoted (escaping quoted specials),
  they were not validated to prohibit CRLF sequences.

  While `Net::IMAP#enable` does process its arguments for aliases, it
  does not validate them as valid atoms (or as a list of valid atoms).
  The `#to_s` value is sent verbatim.

  ### Impact

  This is expected to impact very few users: use of untrusted user input
  for either command is expected to be very uncommon.

  The documentation for `#enable` explicitly warns that using any arguments
  that are not in the explicitly supported list may result in undocumented
  behavior.  Using arbitrary untrusted user input for `#enable` will always
  be inappropriate.

  Although client ID field values will most commonly be static and hardcoded,
  dynamic input sources may be used.  For example, client ID fields may be
  set by configuration or version numbers.  Using untrusted user inputs
  for client ID fields is expected to be uncommon.  But any untrusted
  inputs to client ID can trivially exploit this vulnerability.

  Untrusted inputs to either command may include a CRLF sequence followed
  by a new IMAP command (like DELETE mailbox). Although this does not
  directly enable data exfiltration, it could be combined with other
  attack vectors or knowledge of the target system's attributes,
  e.g.: shared mail folders or the application's installed response handlers.

  ### Mitigation

  Update to a version of `net-imap` which validates `#id` and `#enable`
  arguments.

  Untrusted inputs should _never_ be used for `#enable` arguments.

  If `net-imap` cannot be upgraded:
  * do not use untrusted inputs for client ID field values
  * or add validation that client ID field values must not contain
    any CR or LF bytes.
cvss_v3: 4.3
cvss_v4: 5.8
patched_versions:
  - "~> 0.5.15"
  - ">= 0.6.4.1"
related:
  url:
    - https://www.cve.org/CVERecord?id=CVE-2026-47242
    - https://rubygems.org/gems/net-imap/versions/0.6.4.1
    - https://github.com/ruby/net-imap/releases/tag/v0.6.4.1
    - https://github.com/ruby/net-imap/security/advisories/GHSA-46q3-7gv7-qmgg
    - https://github.com/advisories/GHSA-46q3-7gv7-qmgg
notes: |
  - cve is reserved
  - cvss_v3 - in GHSA ; No cvss_v2, cvss_v4 values.