CVE & CISA-KEV Catalog

CVE-2026-42246

HIGH
7.4
CVSS v3
NVD

Description

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.

CWE-392CWE-393CWE-636CWE-754CWE-841CWE-325

How to fix

Remediation Available
ruby3.4Amazon
Fixed in:0:3.4.8-27.amzn2023.0.6
Fixed in:0:3.4.8-27.amzn2023.0.6
ruby3.4-bundled-gemsAmazon
Fixed in:0:3.4.8-27.amzn2023.0.6
Fixed in:0:3.4.8-27.amzn2023.0.6
ruby3.4-bundled-gems-debuginfoAmazon
Fixed in:0:3.4.8-27.amzn2023.0.6
Fixed in:0:3.4.8-27.amzn2023.0.6
ruby3.4-debuginfoAmazon
Fixed in:0:3.4.8-27.amzn2023.0.6
Fixed in:0:3.4.8-27.amzn2023.0.6
ruby3.4-debugsourceAmazon
Fixed in:0:3.4.8-27.amzn2023.0.6
Fixed in:0:3.4.8-27.amzn2023.0.6
ruby3.4-default-gemsAmazon
Fixed in:0:3.4.8-27.amzn2023.0.6
ruby3.4-develAmazon
Fixed in:0:3.4.8-27.amzn2023.0.6
Fixed in:0:3.4.8-27.amzn2023.0.6
ruby3.4-docAmazon
Fixed in:0:3.4.8-27.amzn2023.0.6
ruby3.4-libsAmazon
Fixed in:0:3.4.8-27.amzn2023.0.6
Fixed in:0:3.4.8-27.amzn2023.0.6
ruby3.4-libs-debuginfoAmazon
Fixed in:0:3.4.8-27.amzn2023.0.6
Fixed in:0:3.4.8-27.amzn2023.0.6
ruby3.4-rubygem-bigdecimalAmazon
Fixed in:0:3.1.8-27.amzn2023.0.6
Fixed in:0:3.1.8-27.amzn2023.0.6
ruby3.4-rubygem-bigdecimal-debuginfoAmazon
Fixed in:0:3.1.8-27.amzn2023.0.6
Fixed in:0:3.1.8-27.amzn2023.0.6
ruby3.4-rubygem-bundlerAmazon
Fixed in:0:2.6.9-27.amzn2023.0.6
ruby3.4-rubygem-io-consoleAmazon
Fixed in:0:0.8.1-27.amzn2023.0.6
Fixed in:0:0.8.1-27.amzn2023.0.6
ruby3.4-rubygem-io-console-debuginfoAmazon
Fixed in:0:0.8.1-27.amzn2023.0.6
Fixed in:0:0.8.1-27.amzn2023.0.6
ruby3.4-rubygem-irbAmazon
Fixed in:0:1.14.3-27.amzn2023.0.6
ruby3.4-rubygem-jsonAmazon
Fixed in:0:2.9.1-27.amzn2023.0.6
Fixed in:0:2.9.1-27.amzn2023.0.6
ruby3.4-rubygem-json-debuginfoAmazon
Fixed in:0:2.9.1-27.amzn2023.0.6
Fixed in:0:2.9.1-27.amzn2023.0.6
ruby3.4-rubygem-minitestAmazon
Fixed in:0:5.25.4-27.amzn2023.0.6
ruby3.4-rubygem-power_assertAmazon
Fixed in:0:2.0.5-27.amzn2023.0.6
ruby3.4-rubygem-psychAmazon
Fixed in:0:5.2.2-27.amzn2023.0.6
Fixed in:0:5.2.2-27.amzn2023.0.6
ruby3.4-rubygem-psych-debuginfoAmazon
Fixed in:0:5.2.2-27.amzn2023.0.6
Fixed in:0:5.2.2-27.amzn2023.0.6
ruby3.4-rubygem-raccAmazon
Fixed in:0:1.8.1-27.amzn2023.0.6
Fixed in:0:1.8.1-27.amzn2023.0.6
ruby3.4-rubygem-racc-debuginfoAmazon
Fixed in:0:1.8.1-27.amzn2023.0.6
Fixed in:0:1.8.1-27.amzn2023.0.6
ruby3.4-rubygem-rakeAmazon
Fixed in:0:13.2.1-27.amzn2023.0.6
ruby3.4-rubygem-rbsAmazon
Fixed in:0:3.8.0-27.amzn2023.0.6
Fixed in:0:3.8.0-27.amzn2023.0.6
ruby3.4-rubygem-rbs-debuginfoAmazon
Fixed in:0:3.8.0-27.amzn2023.0.6
Fixed in:0:3.8.0-27.amzn2023.0.6
ruby3.4-rubygem-rdocAmazon
Fixed in:0:6.14.0-27.amzn2023.0.6
ruby3.4-rubygem-rexmlAmazon
Fixed in:0:3.4.4-27.amzn2023.0.6
ruby3.4-rubygem-rssAmazon
Fixed in:0:0.3.1-27.amzn2023.0.6

This vulnerability affects an unusually large number of packages. The highest-confidence fixes are shown above; the full list is longer. Check the referenced advisories for complete coverage.

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityHigh
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityHigh
IntegrityHigh
AvailabilityNone

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Exploit Intelligence

0.31%probability of exploitation in 30 days
24thpercentile

Low risk: more likely to be exploited than 24% of all known CVEs.

References

Vendor Advisory1

Related Vulnerabilities

Other CWE-392 vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2024-12797Medium6.32.5%-Fix
CVE-2024-39697High8.60.7%-Fix
CVE-2023-42444High8.60.7%-Fix
CVE-2023-48430Low2.70.6%-Fix
CVE-2017-2342High8.10.6%--
CVE-2025-32743Critical9.00.5%-Fix

Common questions

How do I fix CVE-2026-42246?

Published advisories record a fix for 180 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Is CVE-2026-42246 being actively exploited?

Not that we know of. CVE-2026-42246 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.31% is the estimated probability that it will be exploited in the next 30 days. That is higher than 24% of all scored CVEs.

How severe is CVE-2026-42246?

CVE-2026-42246 has a CVSS v3 base score of 7.4, rated important. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-42246 affect?

Published advisories record a fix for ruby3.4 (Amazon), ruby3.4-bundled-gems (Amazon), ruby3.4-bundled-gems-debuginfo (Amazon), ruby3.4-debuginfo (Amazon), and 176 more. The list on this page is capped, so there may be more.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-08-24.