CVE-2026-42245

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.4%, top 67% 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
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.5Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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, Net::IMAP::ResponseReader has quadratic time complexity when reading large responses containing many string literals. A hostile server can send responses which are crafted to exhaust the client's CPU for a denial of service attack. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.

CVSS v3
7.5
EG Score
7.5(medium)
EPSS
33.0%
KEV
Not listed

Published

May 9, 2026

Last Modified

May 18, 2026

Advisory Details (7)

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

Quadratic complexity when reading response literals · Advisory · ruby/net-imap · GitHub

https://github.com/ruby/net-imap/security/advisories/GHSA-q2mw-fvj9-vvcw
generic

Release v0.6.4 · ruby/net-imap · GitHub

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

🔀 Merge pull request #642 from ruby/response_reader-performance · ruby/net-imap@de685f9 · GitHub

https://github.com/ruby/net-imap/commit/de685f91a4a4cc75eb80da898c2bf8af08d34819
generic

🔀 Merge pull request #651 from ruby/backport/v0.4/response_reader-non… · ruby/net-imap@88d9523 · GitHub

https://github.com/ruby/net-imap/commit/88d95231fc8afef11c1f074453f7d75b68c9dfda
generic

🔀 Merge pull request #650 from ruby/backport/v0.5/response_reader-non… · ruby/net-imap@6091f7d · GitHub

https://github.com/ruby/net-imap/commit/6091f7d6b1f3514cafbfe39c76f2b5d73de3ca96

Vendor Advisories for CVE-2026-42245(11)

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

Affected Packages

(1 across 1 ecosystem)
RubyGems(1)
PackageVulnerable rangeFixed inDependents
net-imap0.1.0 ... 0.4.9.1 (45 versions)0.4.24—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 46× 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 108 total refreshes for this CVE.

  1. 2026-07-11 08:27 UTCEPSS rescore
  2. 2026-07-09 19:10 UTCEPSS rescore
  3. 2026-07-08 15:15 UTCEPSS rescore
  4. 2026-07-07 13:46 UTCEPSS rescore
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  16. 2026-06-28 03:43 UTCEG score recompute
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  1. 2026-06-22 14:25 UTCEPSS rescore
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  5. 2026-06-19 19:25 UTCEPSS rescore
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  9. 2026-06-17 01:15 UTCEG score recompute
  10. 2026-06-16 17:52 UTCEPSS rescore
  11. 2026-06-16 07:50 UTCEG score recompute
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  13. 2026-06-15 02:11 UTCEG score recompute
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  20. 2026-06-12 20:00 UTCEG score recompute
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  23. 2026-06-11 14:00 UTCEPSS rescore
  24. 2026-06-11 09:21 UTCEG score recompute
  25. 2026-06-10 22:18 UTCEPSS rescore
  26. 2026-06-10 21:49 UTCEG score recompute
  27. 2026-06-10 13:22 UTCEPSS rescore
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  29. 2026-06-10 10:18 UTCEG score recompute
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  35. 2026-06-08 12:13 UTCEG score recompute
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  37. 2026-06-07 15:25 UTCEPSS rescore
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  39. 2026-06-07 13:10 UTCEG score recompute
  40. 2026-06-07 01:39 UTCEG score recompute
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  42. 2026-06-06 13:47 UTCEPSS rescore
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  44. 2026-06-06 02:35 UTCEG score recompute
  45. 2026-06-05 22:47 UTCEPSS rescore
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  47. 2026-06-05 06:10 UTCEPSS rescore
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  49. 2026-06-05 03:33 UTCEG score recompute
  50. 2026-06-04 16:02 UTCEG score recompute
  51. 2026-06-04 13:12 UTCEPSS rescore
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  53. 2026-06-04 04:30 UTCEG score recompute
  54. 2026-06-03 16:59 UTCEG score recompute
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  56. 2026-06-02 20:13 UTCEPSS rescore
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  60. 2026-06-01 13:52 UTCEPSS rescore
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  63. 2026-05-31 22:30 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2026-42245?
CVE-2026-42245 is a high vulnerability published on May 9, 2026. Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.4.24, 0.5.14, and 0.6.4, Net::IMAP::ResponseReader has quadratic time complexity when reading large responses containing many string literals. A hostile server can send responses which are…
When was CVE-2026-42245 disclosed?
CVE-2026-42245 was first published in the National Vulnerability Database on May 9, 2026, with the most recent update on May 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-42245 actively exploited?
CVE-2026-42245 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 33.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-42245?
CVE-2026-42245 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-42245?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-42245, 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.

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