CVE-2026-42257CRITICAL 9.8EPSS p32.8%

CVE-2026-42257CVE-2026-42257

Description

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.

Scoring

CVSS 3.19.8 (CRITICAL)
VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS0.41% probability of exploitation · percentile 32.8% · 2026-06-18T12:00:27Z
Published2026-05-09
Last modified2026-05-18

Underlying weaknesses· 2

CWE-77CWE-93

References

  1. https://github.com/ruby/net-imap/releases/tag/v0.4.24
  2. https://github.com/ruby/net-imap/releases/tag/v0.5.14
  3. https://github.com/ruby/net-imap/releases/tag/v0.6.4
  4. https://github.com/ruby/net-imap/security/advisories/GHSA-hm49-wcqc-g2xg

2

TypeTargetConfidenceTier
WeaknessImproper Neutralization of Special Elements used in a Command ('Command Injection')cwe-770%live
WeaknessImproper Neutralization of CRLF Sequences ('CRLF Injection')cwe-930%live

Related by meaning· 6

Nearest entities by semantic similarity across the cs-graph corpus.

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CVE-2026-42258
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CVE-2026-48842
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Sourced from NVD + FIRST.org EPSS. Curated for EU compliance use cases by Adam Lundqvist, Founder at SQUR.