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
7.4EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 7.4Exploit: None knownExposed services: Not assessed

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
7.4HIGHmedium confidence
EG Risk
33
EG Risk 33/100

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%
EPSS PROB
0.3%
EPSS %ILE
22nd
KEV
Not listed

Published

May 9, 2026

Last Modified

August 24, 2026

Advisory Details (8)

Auto-updated May 18, 2026
Patch available. Sources: github.
githubMentions a patch (unverified)

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 / EcosystemFix (by version range) / 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 rangeFix by version rangeDependents
ruby2.72.7.4-1 ... 2.7.5-1 (8 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
ruby3.13.1.2-7 ... 3.1.2-8.5 (8 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
ruby3.33.3.8-2, 3.3.8-2.1, 3.3.8-2.2
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
ruby3.33.3.8-2, 3.3.8-2.1, 3.3.8-2.2
  • every version on: no fix on record
—
RubyGems(1)
PackageVulnerable rangeFix by version rangeDependents
net-imap0.1.0 ... 0.3.9 (19 versions)
  • 0.6.0 up to 0.6.4: fixed in 0.6.4
  • 0.5.0 up to 0.5.14: fixed in 0.5.14
  • 0.4.0 up to 0.4.24: fixed in 0.4.24
  • every version up to 0.3.10: fixed in 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 7× in last 7d / 24× 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 202 total refreshes for this CVE.

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

Related CVEs(same product + same vendor + same CWE)

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 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 0.3% probability of exploitation in the next 30 days (22nd percentile of EPSS-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?
A fix for CVE-2026-42246 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-42246 are linked in the Vendor Advisories panel on this page.

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