CVE-2026-42257

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 0.4%, top 64% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.8Exploit: None knownExposed: 0

A fix is available — apply it.

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.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
44(Track)
EG Risk 44/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
37%
KEV
Not listed

Published

May 9, 2026

Last Modified

July 24, 2026

Advisory Details (4)

Auto-updated Sep 12, 2026
Patch available. Sources: github_release, github.
github Patch Available

Command Injection via "raw" arguments to multiple commands · Advisory · ruby/net-imap · GitHub

https://github.com/ruby/net-imap/security/advisories/GHSA-hm49-wcqc-g2xg
github_release Patch Available

v0.6.4

Patch available: ruby/net-imap v0.6.4

https://github.com/ruby/net-imap/releases/tag/v0.6.4
github_release Patch Available

v0.5.14

Patch available: ruby/net-imap v0.5.14

https://github.com/ruby/net-imap/releases/tag/v0.5.14
github_release Patch Available

v0.4.24

Patch available: ruby/net-imap v0.4.24

https://github.com/ruby/net-imap/releases/tag/v0.4.24

Vendor Advisories for CVE-2026-42257(11)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(5)

Vendor / EcosystemFixed in / PatchReleasedSource
ubunturuby3.3-doc (3.3.8-2ubuntu3.1) @ resolute2026-08-23ubuntu
ubunturuby2.3-tcltk (2.3.1-2~ubuntu16.04.16+esm14) @ xenial2026-08-23ubuntu
redhatruby3-3-main-3.3.10-23.4.hum12026-07-15redhat
redhatruby3-4-main-3.4.10-31.hum12026-07-13redhat
redhatruby4-0-main-4.0.5-35.hum12026-07-09redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(5 across 5 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
ruby2.72.7.4-1 ... 2.7.5-1 (8 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
ruby3.13.1.2-7 ... 3.1.2-8.5 (8 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
ruby3.33.3.8-2, 3.3.8-2.1, 3.3.8-2.2——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
ruby3.33.3.8-2, 3.3.8-2.1, 3.3.8-2.2——
RubyGems(1)
PackageVulnerable rangeFixed inDependents
net-imap0.1.0 ... 0.4.9.1 (45 versions)0.4.24—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(2)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 6× in last 7d / 27× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 220 total refreshes for this CVE.

  1. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-17 19:31 UTCEPSS rescore
  3. 2026-09-16 14:08 UTCEPSS rescore
  4. 2026-09-16 05:15 UTCEPSS rescore
  5. 2026-09-13 16:47 UTCEPSS rescore
  6. 2026-09-12 15:01 UTCEPSS rescore
  7. 2026-09-11 14:53 UTCEPSS rescore
  8. 2026-09-11 12:53 UTCOSV refresh
  9. 2026-09-11 09:37 UTCEPSS rescore
  10. 2026-09-10 09:34 UTCEPSS rescore
  11. 2026-09-08 22:00 UTCEPSS rescore
  12. 2026-09-07 16:01 UTCEPSS rescore
  13. 2026-09-06 13:47 UTCEPSS rescore
  14. 2026-09-04 05:06 UTCEPSS rescore
  15. 2026-09-02 14:12 UTCEPSS rescore
  16. 2026-09-01 13:54 UTCEPSS rescore
  17. 2026-08-30 19:17 UTCEPSS rescore
  18. 2026-08-30 01:22 UTCEPSS rescore
  19. 2026-08-28 21:41 UTCEPSS rescore
  20. 2026-08-27 14:25 UTCEPSS rescore
  21. 2026-08-26 14:46 UTCEPSS rescore
  22. 2026-08-25 13:49 UTCEPSS rescore
  23. 2026-08-23 18:49 UTCEG score recompute
  24. 2026-08-23 18:49 UTCVendor advisory
  25. 2026-08-23 00:19 UTCEPSS rescore
Show 75 more
  1. 2026-08-21 23:49 UTCEPSS rescore
  2. 2026-08-20 22:55 UTCEPSS rescore
  3. 2026-08-19 17:03 UTCEPSS rescore
  4. 2026-08-18 13:48 UTCEPSS rescore
  5. 2026-08-17 13:47 UTCEPSS rescore
  6. 2026-08-17 11:26 UTCEG score recompute
  7. 2026-08-17 11:26 UTCVendor advisory
  8. 2026-08-16 14:56 UTCEPSS rescore
  9. 2026-08-16 12:17 UTCVendor advisory
  10. 2026-08-16 08:24 UTCVendor advisory
  11. 2026-08-16 04:30 UTCEG score recompute
  12. 2026-08-16 04:30 UTCVendor advisory
  13. 2026-08-16 02:14 UTCEPSS rescore
  14. 2026-08-15 02:29 UTCEG score recompute
  15. 2026-08-15 02:29 UTCVendor advisory
  16. 2026-08-15 01:30 UTCEPSS rescore
  17. 2026-08-14 22:36 UTCVendor advisory
  18. 2026-08-14 18:43 UTCVendor advisory
  19. 2026-08-14 14:45 UTCVendor advisory
  20. 2026-08-14 10:52 UTCVendor advisory
  21. 2026-08-14 06:58 UTCVendor advisory
  22. 2026-08-14 03:05 UTCEG score recompute
  23. 2026-08-14 03:05 UTCVendor advisory
  24. 2026-08-13 22:00 UTCEPSS rescore
  25. 2026-08-13 08:17 UTCVendor advisory
  26. 2026-08-13 04:22 UTCVendor advisory
  27. 2026-08-13 00:27 UTCVendor advisory
  28. 2026-08-12 20:34 UTCVendor advisory
  29. 2026-08-12 16:40 UTCEG score recompute
  30. 2026-08-12 16:40 UTCVendor advisory
  31. 2026-08-12 13:51 UTCEPSS rescore
  32. 2026-08-11 23:35 UTCVendor advisory
  33. 2026-08-11 19:42 UTCVendor advisory
  34. 2026-08-11 15:49 UTCEG score recompute
  35. 2026-08-11 15:49 UTCVendor advisory
  36. 2026-08-11 13:43 UTCEPSS rescore
  37. 2026-08-11 09:01 UTCVendor advisory
  38. 2026-08-11 05:07 UTCVendor advisory
  39. 2026-08-11 01:14 UTCEG score recompute
  40. 2026-08-11 01:14 UTCVendor advisory
  41. 2026-08-11 00:00 UTCEPSS rescore
  42. 2026-08-10 13:58 UTCVendor advisory
  43. 2026-08-10 09:49 UTCVendor advisory
  44. 2026-08-10 05:55 UTCVendor advisory
  45. 2026-08-10 02:02 UTCVendor advisory
  46. 2026-08-09 22:08 UTCVendor advisory
  47. 2026-08-09 18:15 UTCVendor advisory
  48. 2026-08-09 14:22 UTCEG score recompute
  49. 2026-08-09 14:22 UTCVendor advisory
  50. 2026-08-09 13:46 UTCEPSS rescore
  51. 2026-08-09 10:28 UTCVendor advisory
  52. 2026-08-09 06:13 UTCVendor advisory
  53. 2026-08-09 02:20 UTCEG score recompute
  54. 2026-08-09 02:20 UTCVendor advisory
  55. 2026-08-08 16:37 UTCEPSS rescore
  56. 2026-08-08 11:43 UTCVendor advisory
  57. 2026-08-08 07:43 UTCVendor advisory
  58. 2026-08-08 03:50 UTCVendor advisory
  59. 2026-08-07 23:56 UTCVendor advisory
  60. 2026-08-07 20:03 UTCEG score recompute
  61. 2026-08-07 20:03 UTCVendor advisory
  62. 2026-08-07 16:10 UTCVendor advisory
  63. 2026-08-07 12:14 UTCVendor advisory
  64. 2026-08-07 08:16 UTCVendor advisory
  65. 2026-08-07 01:41 UTCVendor advisory
  66. 2026-08-06 18:54 UTCVendor advisory
  67. 2026-08-06 15:01 UTCEG score recompute
  68. 2026-08-06 15:01 UTCVendor advisory
  69. 2026-08-06 13:46 UTCEPSS rescore
  70. 2026-08-06 10:08 UTCVendor advisory
  71. 2026-08-06 05:52 UTCVendor advisory
  72. 2026-08-06 01:58 UTCVendor advisory
  73. 2026-08-05 22:05 UTCEG score recompute
  74. 2026-08-05 22:05 UTCVendor advisory
  75. 2026-08-05 19:17 UTCEPSS rescore

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-42257?
CVE-2026-42257 is a critical vulnerability published on May 9, 2026. 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…
When was CVE-2026-42257 disclosed?
CVE-2026-42257 was first published in the National Vulnerability Database on May 9, 2026, with the most recent update on July 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-42257 actively exploited?
CVE-2026-42257 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 63.3% of all scored CVEs.
What is the CVSS score of CVE-2026-42257?
CVE-2026-42257 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-42257?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-42257, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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