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Command InjectionWeakness · CWE-77

CVE-2026-47242

MEDIUM · 5.8 CVSS v4.0 Published 2026-06-22
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
61/100
Remediation priority · Elevated
No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to 0.6.5 and 0.5.15, 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. Arguments to either command could be used by an attacker to inject arbitrary IMAP commands. This vulnerability is fixed in 0.6.5 and 0.5.15.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Net::IMAP Ruby library versions before 0.6.5 and 0.5.15 allow injection of arbitrary IMAP commands. The #id method doesn't validate hash argument values to prohibit CRLF sequences (allowing command injection via line breaks), and the #enable method doesn't validate arguments as valid atoms, sending #to_s values verbatim without sanitization.

MitigationUpgrade to Net::IMAP version 0.6.5 or 0.5.15 which adds proper input validation to prevent CRLF injection in the ID command and atom validation in the ENABLE command.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
None
Authentication
X
User interaction
P
Scope
X

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check Net::IMAP version
    Run 'gem list net-imap' or inspect your Gemfile.lock for the net-imap gem version
    Affected if version is before 0.6.5 or between 0.5.0 and 0.5.15 (0.5.x versions before 0.5.15)
  2. Find Net::IMAP usage in codebase
    Search source files for 'Net::IMAP.new' or 'require "net/imap"' to locate IMAP client code
    Affected if Net::IMAP is used in the application
  3. Check for #id method calls
    Search for calls to the #id method on Net::IMAP objects, e.g., 'imap.id(some_hash)' where some_hash values could be user-controlled
    Affected if the #id method is called with hash values containing unvalidated input
  4. Check for #enable method calls
    Search for calls to the #enable method on Net::IMAP objects, e.g., 'imap.enable(some_argument)' where some_argument could be user-controlled
    Affected if the #enable method is called with arguments derived from unvalidated input

You are affected if your Net::IMAP version is below 0.6.5 or below 0.5.15 AND your code calls the #id or #enable methods with unvalidated user input.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to Net::IMAP version 0.6.5 or 0.5.15 which adds proper input validation to prevent CRLF injection in the ID command and atom validation in the ENABLE command.

Recommended fix High confidence

net-imap version 0.6.5 or 0.5.15 (or newer)

  1. Identify the current Net::IMAP version in your project by running `gem list net-imap` or checking your Gemfile
  2. Run `gem install net-imap` to install the latest version, which will include 0.6.5 or newer
  3. Alternatively, update your Gemfile to specify `gem 'net-imap', '~> 0.6.5'` or `gem 'net-imap', '~> 0.5.15'` and run `bundle update net-imap`
  4. After updating, verify the installed version with `gem list net-imap` to confirm either 0.6.5+ or 0.5.15+ is installed
  5. Test your application to ensure IMAP functionality works correctly after the upgrade

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,040
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-47242 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
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