CVE-2026-42246

HIGHNVD 7.47.4—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.4 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 76% 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
Trending — 3 sources updated this week
7.4EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.4Exploit: None knownExposed: 0

A fix is available — apply it.

Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.3.10, 0.4.24, 0.5.14, and 0.6.4, a man-in-the-middle attacker can cause Net::IMAP#starttls to return "successfully", without starting TLS. This issue has been patched in versions 0.3.10, 0.4.24, 0.5.14, and 0.6.4.

CVSS v3
7.4
EG Score
7.4(medium)
EG Risk
33(Track)
EG Risk 33/100SSVC: 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
Severity74% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
23%
KEV
Not listed

Published

May 9, 2026

Last Modified

August 24, 2026

Advisory Details (8)

Auto-updated May 18, 2026
Patch available. Sources: github.
github Patch Available

STARTTLS stripping via invalid response timing · Advisory · ruby/net-imap · GitHub

https://github.com/ruby/net-imap/security/advisories/GHSA-vcgp-9326-pqcp
generic

Release v0.5.14 · ruby/net-imap · GitHub

https://github.com/ruby/net-imap/releases/tag/v0.5.14
generic

Release v0.4.24 · ruby/net-imap · GitHub

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

Release v0.3.10 · ruby/net-imap · GitHub

https://github.com/ruby/net-imap/releases/tag/v0.3.10
generic

🔀 Merge pull request #665 from ruby/backport/v0.5/STARTTLS-stripping · ruby/net-imap@f79d35b · GitHub

https://github.com/ruby/net-imap/commit/f79d35bf5833f186e81044c57c843eda30c873da
generic

🔀 Merge pull request #667 from ruby/backport/v0.3/STARTTLS-stripping · ruby/net-imap@97e2488 · GitHub

https://github.com/ruby/net-imap/commit/97e2488fb5401a1783bddd959dde007d9fbce42c
generic

🔀 Merge pull request #666 from ruby/backport/v0.4/STARTTLS-stripping · ruby/net-imap@24a4e77 · GitHub

https://github.com/ruby/net-imap/commit/24a4e770b43230286a05aa2a9746cdbb3eb8485e
generic

🔀 Merge pull request #664 from ruby/security/STARTTLS-stripping · ruby/net-imap@0ede4c4 · GitHub

https://github.com/ruby/net-imap/commit/0ede4c40b1523dfeaf95777b2678e54cc0fd9618

Vendor Advisories for CVE-2026-42246(20)

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

Patch Availability(23)

Vendor / EcosystemFixed in / PatchReleasedSource
ubunturuby2.3-tcltk (2.3.1-2~ubuntu16.04.16+esm14) @ xenial2026-08-24ubuntu
ubunturuby3.0-doc (3.0.2-7ubuntu2.13) @ jammy2026-08-24ubuntu
redhatruby3-4-main-3.4.10-31.hum12026-07-13redhat
redhatruby:3.3-9060020260630075016.92026-07-09redhat
redhatruby-0:2.0.0.648-39.el7_9.12026-07-09redhat
redhatruby:3.3-9040020260630065449.92026-07-07redhat
redhatruby-0:3.3.10-11.el10_0.22026-07-06redhat
redhatruby:2.5-8040020260630124058.522a0ee42026-07-06redhat
redhatruby:2.5-8060020260630123825.ad008a3a2026-07-06redhat
redhatruby-0:3.0.4-161.el9_2.32026-07-06redhat
redhatruby:2.5-8080020260625114827.63b345852026-07-01redhat
redhatruby:4.0-9080020260619130154.92026-06-30redhat
redhatruby-0:3.0.7-167.el9_82026-06-30redhat
redhatruby3-4-main-3.4.8-31.2.hum12026-06-30redhat
redhatruby4.0-0:4.0.3-35.el10_22026-06-30redhat
redhatruby-0:3.3.10-13.el10_22026-06-30redhat
redhatruby:2.5-8100020260615131019.489197e62026-06-30redhat
redhatruby3-3-main-3.3.10-23.2.hum12026-06-30redhat
redhatruby:3.3-9080020260615131001.92026-06-30redhat
redhatruby-0:3.0.7-162.el9_4.32026-06-30redhat
redhatruby:3.3-8100020260615131010.489197e62026-06-30redhat
redhatruby4-0-main-4.0.0-33.4.hum12026-06-30redhat
redhatruby-0:3.0.7-165.el9_6.12026-06-30redhat

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 ... 0.3.9 (19 versions)0.3.10—

Weakness Classification(6)

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

Additional Vendor Advisories

(3)

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 10× in last 7d / 72× 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 168 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-42246?
CVE-2026-42246 is a high vulnerability published on May 9, 2026. Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.3.10, 0.4.24, 0.5.14, and 0.6.4, a man-in-the-middle attacker can cause Net::IMAP#starttls to return "successfully", without starting TLS. This issue has been patched in versions 0.3.10,…
When was CVE-2026-42246 disclosed?
CVE-2026-42246 was first published in the National Vulnerability Database on May 9, 2026, with the most recent update on August 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-42246 actively exploited?
CVE-2026-42246 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 76.6% of all scored CVEs.
What is the CVSS score of CVE-2026-42246?
CVE-2026-42246 has a CVSS v3 base score of 7.4 (NVD).
How do I remediate CVE-2026-42246?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-42246, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-42246

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